� 2020 Published by Elsevier Inc. on behalf of Poultry Science Association Inc. This is an open access article under the CC BY-NC-ND license(http://creativecommons.org/licenses/by-nc-nd/4.0/).

Equipment and methods for poultry euthanasia by asingle operator

R. S. Boyal,* R. J. Buhr,† C. E. Harris,†,‡ L. Jacobs,§ and D. V. Bourassa*,1

*Department of Poultry Science, Auburn University, Auburn, AL 36849, USA; †PoultryMicrobiological Safety and Processing Research Unit, U.S. National Poultry Research

Center, Richard B. Russell Agricultural Research Center, USDA-ARS, Athens, GA 30605,USA; ‡Department of Poultry Science, The University of Georgia, Athens, GA 30602,USA; and §Department of Animal and Poultry Sciences, Virginia Tech, Blacksburg, VA

24061, USA

Primary Audience: Flock Supervisors, Researchers, Veterinarians

SUMMARY

Euthanasia of large poultry can be particularly challenging due to the difficulty of manualcervical dislocation of large older birds. Euthanasia is intended to swiftly render the animalunconscious and rapidly lead to death using humane methods. Euthanasia by a single operatorcan be challenging when euthanizing mature broiler breeders and turkeys weighing from 4 to30 Kg. Owing to the difficulty of manual cervical dislocation on large poultry, developmentand assessment of alternative methods for euthanasia are necessary. Four American VeterinaryMedical Association approved alternative euthanasia methods including mechanical cervicaldislocation, nonpenetrative captive bolt, carbon dioxide, and electrical euthanasia were eval-uated on broiler breeders, Beltsville Small White turkeys, and Broad Breasted White turkeys. Amobile bird euthanasia apparatus was designed allowing for individual bird euthanasia by asingle operator. Mechanical cervical dislocation and nonpenetrative captive bolt devices werecommercially available. The carbon dioxide and electrical euthanasia devices used weredeveloped for this work. Each of the 4 euthanasia methods were assessed for kill successdefined as one euthanasia attempt with no signs of recovery. In addition, the costs associatedwith purchase or construction of each device are reported. All four euthanasia methods resultedin successful euthanasia of 436 birds. The overall single application euthanasia success rateswere 97% for mechanical cervical dislocation, 98% for captive bolt, 97% for carbon dioxide,and 99% for electrical euthanasia. Each method can be used to successfully euthanize broilerbreeders and turkeys and can be used safely when the use of manual cervical dislocation is notfeasible.

Key words: broiler breeder, euthanasia, turkey

2020 J. Appl. Poult. Res. 29:1020–1032https://doi.org/10.1016/j.japr.2020.09.010

1Corresponding author: dvb0006@auburn.edu

BOYAL ET AL: POULTRY EUTHANASIA METHODS 1021

DESCRIPTION OF PROBLEM

According to the American VeterinaryMedical Association (AVMA), euthanasia is “amatter of humane disposition” that occurs whenthe animal’s continued existence is no longer arational option “as perceived by the owner andveterinarian” (AVMA, 2020). The most com-mon method for euthanizing poultry on-farm ismanual cervical dislocation (CD). Cervicaldislocation requires the mastering of technicalskills to ensure loss of consciousness is rapidlyinduced. For CD on poultry and other birds, thelegs or wings of the bird are grasped in one handand the neck then stretched by pulling on thehead while applying a backward rotational forceto the skull (AVMA, 2020). Even though CD iscommonly used and considered humane, inprevious studies, brainstem neural reflex activitywas found to continue for up to 30 s after CD(Gregory and Wotton, 1990; Jacobs et al.,2019). However, the immediate display ofclonic-tonic convulsions indicates that the birdswere considered immediately unconscious andunable to perceive pain in the cerebral cortex ofthe brain after CD (Woolcott et al., 2018a;Jacobs et al., 2019). Euthanasia with CD isdifficult on larger birds so commercially avail-able alternatives such as the Koechner Eutha-nizing Device (KED) (Clear View Enterprises,LLC., Tontitown, AR) and the Turkey Eutha-nasia Device (TED) (Bock Industries, Inc.Philipsburg, PA) have been developed. Inaddition to KED and TED, other provisionalAVMA-approved alternative methods to CD forindividual bird euthanasia include carbon diox-ide (CO2), electrical euthanasia, and blunt headtrauma.

Koechner Euthanizing Device is a tooldeveloped for mechanical cervical dislocationfor use in separating the skull from the verte-brae. One advantage of mechanical cervicaldislocation is that it is more consistently appliedthan CD in euthanizing larger and mature birdssuch as turkeys, broiler breeders, or older layersbecause it can be applied uniformly, requiresless strength, and less training. The strengthrequired to manually dislocate the skull from theneck could be too great, resulting in incompleteseparation of the skull from the vertebrae andtherefore unsuccessful or prolonged euthanasia.

In a previous study comparing the KED withCD on broilers, both methods induced rapidunconsciousness as indicated by immediateclonic/tonic convulsions; however, the persis-tence of induced eye reflexes suggested that theKED method took longer to induce brainsteminsensibility and brain death (Woolcott et al.,2018a). The authors noted that a disadvantageof using CD is that the size of the bird can affectefficacy because some birds may be too largeand heavily muscled to properly restrain anddislocate the head from the neck by a singleoperator.

Nonpenetrating captive bolt guns, specif-ically TED, have been developed and success-fully used for euthanasia of young pigs,neonatal ruminants, and poultry. The turkeyEuthanasia Device can be used to euthanizepoultry in a range of weights from 3.5 kg (7.7lb) chickens to 20 kg (44 lb) turkeys with nearinstantaneous absence of an induced nictitatingmembrane response (brainstem insensibility)within 2 s due to brain hemorrhage and swellingand 100% kill success within 2 min (Hulet et al.,2013; Gibson et al., 2018). In a previous study,brainstem reflexes were used as indicators ofinsensibility (brainstem death) and the cessationof convulsions (spinal cord death) and sustainedabsence of breathing (brainstem death) wereused as indicators of irreversible brainstem andspinal cord failure and death in broiler turkeys(4.1 kg) that were euthanized with manual cer-vical dislocation, blunt trauma, or a non-penetrating captive bolt gun (Erasmus et al.,2010). Cervical dislocation was found to resultin a shorter length of time until convulsionsceased (spinal cord death) when compared withthe birds euthanized by blunt trauma or acaptive bolt gun. However, birds euthanizedwith blunt trauma or captive bolt had a similareffect of causing immediate insensibility asinterpreted by the observed initiation of clonic/tonic convulsions.

Euthanasia with inhaled agents can be admin-istered by various methods depending on the cir-cumstances and equipment available. The AVMArecommends CO2 gas as being acceptable foreuthanasia because of it being “inexpensive,nonflammable, and nonexplosive and poses min-imal hazard to personnel when used with properlydesigned equipment” (AVMA, 2020). Although

1022 JAPR: Research Report

there is no flow rate requirement, previous studieson euthanasiawith CO2 have found that to preventpossible discomfort, a gradual increase of CO2 isrecommended which is in agreement with AVMArecommendations (Gerritzen et al., 1997; AVMA,2020).

The AVMA also recommends electricaleuthanasia if the birds are rendered unconsciousthrough electrical AC current passing throughthe brain before or simultaneously with the heart(AVMA, 2020). Passing an electrical currentsimultaneously through the brain and heart isconsidered a 1-step head-to-body approach.Electrical euthanasia has the advantage of beingeconomical but also requires adequate knowl-edge of electrical current properties to preventhazards to personnel and to ensure the passageof current through both the heart and brain ofthe bird. A potential cause of failure to induceunconsciousness with electrical euthanasia canbe incorrect placement or inadequate contact ofthe clip electrodes (Grandin, 2001).

The use of these euthanasia methods can bechallenging for a single operator, which isfrequently a necessity on farm. The purpose ofthis work was to describe the development of amobile bird euthanasia apparatus (MBEA) forindividual bird euthanasia by a single operator,describe application of the commercially avail-able KED and TED euthanasia methods, detailthe construction and use of systems for CO2 andelectrical euthanasia, and to evaluate each ofthese euthanasia methods for use on individuallarge poultry including adult broiler breedersand market age turkeys.

MATERIALS AND METHODS

All animal handling procedures used in thisstudy were approved by the Auburn UniversityInstitutional Animal Care and Use Committee(PRN #2018-3327). On five separate days eacheuthanasia method was performed on a total oftwo hundred sixty two 65-wk-old broiler breeders(131 males and 131 females) with the maleshaving an average body weight of 4.4 kg and thefemales having an average body weight of 3.9 kg.On two separate days (67- and 38-wk-old) eacheuthanasia method was performed on a total of120 Beltsville Small White (BSW) turkeys (76

males, 6.9 kg (both ages) and 44 females, 3.5 kg(only at 67 wk)). On one day, each euthanasiamethod was performed on a total of fifty four 21-wk-old Broad BreastedWhite (BBW) turkeys (23males, 18.8 kg and 31 females, 12.8 kg).

Broiler breeders were obtained from a com-mercial flock at the end of lay, transported to theAuburn University poultry research farm wherethey were housed for 1 to 2 wk in floor penscovered with wood shavings, 20 males or fe-males per pen. Broiler breeders had not been fedthe morning on each day of euthanasia. Eachpen of birds was caught, individually weighed,and 4 birds placed into each plastic coop (Pak-ster, Athens, TN), 1 breeder/coop was assignedto each method of euthanasia. The BSW turkeyswere cooped while fullfed and transported fromthe barn to the holding area in the pilot pro-cessing plant in 3 or 4 batches of 20 birds at 3 hintervals each day. Individual turkeys wereremoved from the coop, weighed, and assigneda euthanasia method. The BBW turkeys wererange penned with access to water, individuallycaught and weighed, alternating between 4 tomsfollowed by 4 hens for each euthanasia method.

After the application of each euthanasiamethod, kill success was recorded with either ayes or no result at 4 min after application. Killsuccess was defined as only one euthanasiaattempt on the bird with no signs of recovery asobserved by the absence of reinitiation of respi-ration (Martin et al., 2016; Gibson et al., 2018).

Mobile Bird Euthanasia Apparatus

An MBEAwas developed for use by a singleoperator, for individual bird euthanasia(Figure 1). The MBEAwas assembled with a 28in. PVC traffic cone (J. J. Keller & Associates,Inc., Neenah, WI) secured onto a gas cylindercart (Dayton Electric, Lake Forest, IL). Thecone was secured onto the cart with the attachedsafety chain. The small end of the traffic conewas trimmed to accommodate the desired birdsize and to provide a place to add a bucket ifblood loss were to occur. For each of theeuthanasia methods, individual birds (broilerbreeders and BSW turkeys) were inserted intothe MBEA with their head extending out of thebottom and a bucket was placed below the coneto collect blood after method application. When

Figure 1. The mobile bird euthanasia apparatus (MBEA) is constructed from a PVC traffic cone and gas cylindercart. The space below the traffic cone may allow for placement of a 5 gal bucket to capture blood lost during andafter euthanasia.

BOYAL ET AL: POULTRY EUTHANASIA METHODS 1023

euthanizing BBW turkeys, larger sized metalbleeding cones for slaughter were required.

Standard personal protective equipment forhandling live poultry included boots, scrubs orlong pants and shirts, disposable plastic aprons,and gloves (latex or nitrile). Initial trials deter-mined that a face shield was not requiredbecause blood, crop contents, and/or feces werecontained within the plastic bucket or trafficcone. Personnel training for TED and KEDconsisted of reading the manufacturer brochuresprovided with the equipment, watching the on-line videos, preparing SOPs that were approvedby the attending veterinarian. Training for CO2

consisted of following the approved SOP for theeuthanasia of poultry using CO2 as adapted foruse in the MBEA. Training for electrocutionconsisted of following the approved SOP foreuthanasia of poultry using electrocution asadapted for use in the MBEA.

Koechner Euthanizing Device–MechanicalCervical Dislocation

For the broiler breeders and BSW turkeys, theKED-C, which has an overall length of 69 cm(27 in) and is recommended for birds from 5.4 kg

(12 lbs) up to 13.6 kg (30 lbs), was used to performeuthanasia (Clear View Enterprises). For theBroad BreastedWhite turkeys, KED-T, which hasan overall length of 102 cm (40 in) and is rec-ommended for birds from 5.4 kg (12 lbs) up to 75lbs (34.0 kg), was used. To begin the euthanasiaprocess, the bird was placed into the MBEA andthe operator positioning the KED with the doubleblade behind the jaw while the single blade waspositioned directly at the base of the skull andperpendicular to the head and neck, and medianplane of the body (Figure 2). Then the operatorclosed the KED until the jaws were lightlytouching the bird’s neck. Next, the operatorbrought the handles fully together swiftly until a“click” was heard, which indicated that the bladestops had touched. After the handles were broughttogether, the KED was removed from the neckwithin 2 s. Once convulsions ended, the operatorchecked for physiological responses includinglack of respiration or physical movement andrecorded a yes or no result for kill success at 4min.

Turkey Euthanasia Device–Captive Bolt

The TED was utilized for broiler breeder andturkey euthanasia in accordance with the

Figure 2. The Koechner Euthanizing Device (KED) isplaced around the neck at the base of the head beforeclosure. Securing the bird in the mobile bird euthanasiaapparatus (MBEA) minimizes physical activity beforeand after euthanasia.

Figure 3. The Turkey Euthanasia Device (TED) isplaced on the back of the head just behind the comb.The adapter should be in firm contact with the headbefore firing. Securing the bird in the mobile birdeuthanasia apparatus (MBEA) minimizes physicalactivity before and after euthanasia.

1024 JAPR: Research Report

manufacturer’s instructions (Bock Industries,Inc.). When the TED was ready for use, theactivator was pushed back, and test fired. Tobegin the euthanasia process, the bird wasplaced into the MBEA, the activator was thencocked and positioned at the base of the comb(broiler breeders, Figure 3), or between a centerpoint for the back of the eyes and the ears(turkeys). The trigger was pulled when the TEDwas fully in contact with the head. After appli-cation of TED euthanasia, the bird lost bloodwhich was collected in a bucket placed belowthe MBEA cone. Once convulsions ended andbefore disposal, death was confirmed by lack ofrespiration or physical movement at 4 min.

Carbon Dioxide Euthanasia

Gas asphyxiation (hypoxia) with CO2 wasutilized as another AVMA approved form ofeuthanasia for large poultry (AVMA, 2020). Amobile apparatus using CO2 was developedusing affordable components that are easilyobtainable. In addition, a commercial versionhas recently been developed and is commer-cially available (QC Supply, Schuyler, NE). The

CO2 euthanasia system was constructed using a567 g (20 oz) CO2 gas cylinder (TippmannSports, Fort Wayne, IN) attached by an adapter(Interstate Pneumatics, Vista, CA) to a low-pressure regulator (Micro Matic, Brooksville,FL, Figure 4). A large plastic container with anapproximate volume of 2,912 cm3 was config-ured by cutting a hole in the lid large enough toaccommodate the birds head and neck, cutting ahole at the bottom of a gallon-sized plastic bag,then securing the plastic bag to the lid with tapeto avoid gas escape. To route the CO2 from thetank to the container, a small hole was drilledinto the side of the container and a 0.95 cm (3/8in) by 0.64 cm (1/4 in) nylon barbed elbow (BKProducts, Collierville, TN) was inserted. Thenclear vinyl PVC flexible tubing 1.27 cm (1/2 in)outside diameter by 0.95 cm (3/8 in) insidediameter (Rollerflex, Elizabeth, NJ) wasattached to the elbow fitting and CO2 low-pressure regulator.

To begin the euthanasia process, the bird wasplaced into the MBEA, then the CO2 regulatorwas adjusted to 5 PSI with the hose valves

Figure 4. The carbon dioxide (CO2) euthanasia systemis constructed from a 20 oz CO2 tank, regulator, hose,plastic chamber, and accessories and allows forhead-only, single bird euthanasia.

BOYAL ET AL: POULTRY EUTHANASIA METHODS 1025

closed. The bird’s head was then insertedthrough the plastic bag and into the container.The operator then gently held the bag closedaround the neck of the bird with one hand whileslightly opening the regulator valve until CO2

release into the tube was audible for 20 s. Thegoal of this initial CO2 exposure was to gradu-ally increase CO2 concentration leading to atwo-phase euthanasia process. After 1 min hadelapsed, the operator slightly opened the valveagain for an additional 30 s. Using this protocol,CO2 concentration was maintained below 60%for the first minute and above 70% for theremaining time of euthanasia completion withina total of 4 min. The concentrations of CO2

were measured with a F-920 Check It! gasanalyzer (Felix Instruments, Camas, WA) todetermine the time necessary to achieve agradual gas concentration increase and maintainhigh levels of CO2 for euthanasia completion.However, a gas analyzer should not be requiredby end users if the suggested standard valveopen/close operating procedures are followed.After a total CO2 exposure time of 4 min andconvulsions ended, death was confirmed by lack

of respiration or physical movement at anadditional 4 min.

Electrical Euthanasia

The electrical euthanasia apparatus wasconstructed with parts purchased at a localhardware store (Figure 5). The device wasconstructed with an exterior watertight electricalbox (Sigma Electric, Garner, NC) with a groundfault outlet (Legrand, West Hartford, CT) onone side and a toggle switch (Legrand, WestHartford, CT) on the other side. Then an out-door cord (ULINE, Pleasant Prairie, WI) waswired through a waterproof conduit fitting(Sigma Electric, Garner, NC) to the electricalbox with the other end available to plug into anoutlet. An indoor cord (Value Tech Supply,Boca Raton, FL) and battery clips (GardnerBender, New Berlin, WI) were then wired andsoldered together to be plugged into the outleton the electrical euthanasia device. The devicehas 2 built-in safety features, an indicator light(Ace Hardware, Oak Brook, IL) insert in agrounding adapter (Leviton ManufacturingCompany, Inc., Melville, NY) which allows theuser to visually determine whether electricity ison, and the ground fault circuit interrupter(GFCI) outlet to protect the end user fromelectrical shock. The instant GFCI detects cur-rent leakage as low as 0.005 Amps, it trips and“breaks” the circuit. Attached to the top of thedevice is a weatherproof electrical box cover(Sigma Electric, Garner, NC) to prevent waterfrom entering the electrical box when the deviceis not in use or during sanitization.

Before use for euthanasia, the device wastested for the presence of electricity. This wascarried out by the operator plugging the currentindicator light into one outlet on the electricaleuthanasia device and turning the switch to off.Then the outdoor cord was plugged into anelectrical outlet. The operator then turned thetoggle switch to on and the current indicatorlight turned on, indicating that electricity waspresent at the outlet and the ground fault active.Next the toggle switch on the electrical eutha-nasia device was switched to off and the clipswere plugged into the second GFCI outlet onthe electrical euthanasia box. While the bird wasrestrained in the MBEA, the operator attached

Figure 5. The electrical euthanasia device is assem-bled from common components available at home orhardware stores.

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one clip to the vent first and then the other clipto the jaw. The clip was attached to the vent firstto minimize the length of time discomfort wasexperienced by the bird after clamping of thelower jaw. The operator then immediatelyturned on the electrical euthanasia box for 15 s.After that time, the electrical current was turnedoff at the switch then the electrode clips wereremoved. The bird was then confirmed dead bylack of respiration or physical movement within4 min.

Statistical Analysis

Kill success is defined as no detection of anymovements at 4 min after application of eutha-nasia methods. The period of 4 min was selectedto assure that death had occurred, inclusive ofcerebral cortex brain death, brainstem death,and spinal cord death, and was based on twicethe period required for poultry to recover forelectrical stunning at slaughter (Bourassa et al.,2017) and the 3 min minimum exposure dura-tion commonly used for controlled atmospherestunning including low atmospheric pressure(Turcsán et al., 2001; Purswell et al., 2007;Holloway and Pritchard 2017). Kill success data

were statistically analyzed by chi-square anal-ysis of SAS University Edition (SAS InstituteInc., Cary, NC) with main effects of sex andeuthanasia method. Significant differences weredetermined at P , 0.05.

RESULTS AND DISCUSSION

There were no significant differences detec-ted for single application kill success betweensexes or among euthanasia methods for broilerbreeders, BSW, or BBW turkeys. For broilerbreeders, TED and electrical euthanasia were100% successful (69/69, 70/70) followed byKED and CO2 (58/59, 62/64), Table 1. The twobroiler breeders not successfully euthanized byCO2 in a single 4 min application reinitiatedrespiration on removal from the CO2 device.One of these 2 was caused by equipment errorwhere not enough gas was added to the device.It is unknown why the other bird was able torecover. For the one broiler breeder that was notsuccessfully euthanized by KED-C in a singleapplication, there appeared to be only partialseparation of the skull from the spinal cord asdetermined by manual palpation and respirationhad reinitiated. All birds that reinitiated respi-ration were immediately subjected to electricaleuthanasia.

For the BSW turkeys, electrical euthanasiawas 100% successful (29/29) followed by TED,CO2, and KED (30/31, 29/30, 28/30, respec-tively). The BSW turkey not successfullyeuthanized with a single TED application mayhave been due to operator error where the de-vice was not firmly seated on the skull when thetrigger was pulled, but was correctly positionedbetween the eyes and the ears. The CO2 misskill occurred because the turkey had removed itshead from the gas container and reinitiatedrespiration. The two KED miss kills were theresult of muscular movements that persistedbeyond the 4 min after application period,although respiration was not reinitiated andphysical movement ceased within 1 additionalmin.

For the BBW turkeys, KED-T and CO2 were100% successful (12/12, 13/13) followed by TEDand electrical euthanasia (12/13, 15/16). The misskill for TED was due to off center placement

BOYAL ET AL: POULTRY EUTHANASIA METHODS 1027

(approximately 1 cm) and the thickness of thecaruncle onheadof amale turkey. Themiss kill forthe electrical euthanasia was inadequate place-ment of the electrodes on the exterior and not inthe vent. In addition, both of these miss killsoccurred near the end of the sampling day (turkeyssampled 32nd and 48th), and the turkeys were wetfrom rain which may have contributed to operatorfatigue and lack of concentration during eutha-nasia method application.

Mobile Bird Euthanasia Apparatus

With utilization of theMBEA, all 4 methods ofeuthanasia were able to be performed by a singleoperator. In addition to restricting physical activ-ity, securing the bird has the potential to improvethe operator’s safety and allow for a single oper-ator to be mobile while performing any of theeuthanasia methods. Owing to the convulsionsthat occur after euthanasia using KED or TED,securing the bird during application of euthanasiais beneficial for operator safety after euthanasia(Erasmus et al., 2010; Woolcott et al., 2018b) aswell as minimizing flock distress with restrictedconvulsions. Securing the bird also allows for theoperator to have both hands free before, during,and after performing each method. Although ametal bleeding cone would also adequatelycontain the bird, a PVC traffic cone is noncon-ductive allowing utilization for multiple methodsof euthanasia, allows for customization of theopening to account for bird sizes on the farm, andminimizes the noise that is generated in metalcones during convulsions. When euthanizing thelarger Broad Breasted White turkeys by KED,TED, and CO2, the PVC traffic cone was replacedwith a larger commercially available turkey pro-cessing metal bleeding cone (Cornerstone FarmVentures, Moravian Falls, NC). Postapplicationconvulsions following both the KED and TEDmethods were severe enough to cause the metalcones to become deformed. Convulsions did notappear to be as severe during CO2 euthanasiamethod (visual observation, not measured). Forelectrical euthanasia of poultry, the cone utilizedfor euthanasia must be composed of a noncon-ductive material to minimize current leakage fromthe carcass and tripping theGFCI. In thiswork, theBroad BreastedWhite turkeys were too large to fitinto the traffic cones, so thereforewere placed on a

plastic cart on their breast and held by the feet untilapplication of electrical euthanasia. For future useof the MBEA and electrical euthanasia, largeturkey cones can be fabricated from nonconduc-tive materials such as plastic sheeting.

Koechner Euthanizing Device–MechanicalCervical Dislocation

The KED is a commercially availableeuthanasia device with detailed application in-structions available on the Clear View Enter-prise website (model #: 8152605, Clear ViewEnterprises, LLC., Tontitown, AR). KoechnerEuthanizing Device is designed to replacemanual cervical dislocation with mechanicalcervical dislocation. However, in a previousstudy conducted to assess the onset of braindeath of broilers euthanized by the KED andCD, nictitating membrane reflexes, mouthgaping reflexes, and musculoskeletal movementendured for a longer time in birds euthanized byKED when compared with CD (Jacobs et al.,2019). Based on these results, the researchersconcluded that manual cervical dislocationwould be the recommended method for broilereuthanasia. When KED was compared with CDor intravenous pentobarbital sodium on turkeys(8 wk of age), the time to isoelectric brain ac-tivity was prolonged in both CD (239 s) andKED (278 s) euthanized birds (Hernandez et al.,2019). However, this does not indicate at whatpoint the bird achieved unconsciousness (onsetof convulsions, Raj et al., 1990; Dawson et al.,2007) and it is not reasonable to expect the enduser to perform euthanasia on farm usingintravenous pentobarbital sodium and complywith disposal restrictions of pentobarbitalcontaminated carcasses that are not acceptablefor rendering (FDA, 2003).

For this report, 3 of 101 birds were not suc-cessfully euthanized using the KED euthanasiamethod. Although the KED euthanasia methodcan require a longer time to attain death, KED isa useful alternative in cases where personnel thatneed to perform euthanasia are minimallytrained, not yet skilled or comfortable using CD,are not physically capable of performing CD, orneed to euthanize numerous birds (.70/person/day, European Union Council Regulation No1099/20090, European Union Council

Tab

le1.

Age

,ge

nder,an

dkillsu

cces

sforbroilerbree

ders,Beltsville

SmallW

hite,an

dBroad

Breas

tedWhite

turkey

seu

than

ized

with

aKoe

chne

rEutha

nizing

Dev

ice,

Turke

yEutha

nasiaDev

ice,

carbon

diox

ide,

orelec

trical

euthan

asia.

Param

eter

Broilerbreeders

Beltsville

SmallWhite

Broad

BreastedWhite

Age

65wk

67,38

,67

wk

21wk

Gender

MF

MF

MF

Bodyweight(kg)

4.4

3.9

6.9

3.5

18.8

12.8

Euthanasiamethodkillsuccess1

Total

Total

Total

KoechnerEuthanizing

Device(K

ED)2

29/30

29/29

58/59

20/20

8/10

28/30

5/5

7/7

12/12

TurkeyEuthanasiaDevice(TED)3

32/32

37/37

69/69

16/17

14/14

30/31

5/6

7/7

12/13

Carbondiox

ide(CO2)4

33/34

29/30

62/64

19/20

10/10

29/30

6/6

7/7

13/13

Electricaleuthanasia5

35/35

35/35

70/70

19/19

10/10

29/29

6/6

9/10

15/16

1Kill

successisdefinedas

oneeuthanasia

attempt

with

nosign

sof

mov

ementor

recovery

(respiratio

n)with

in4min

afterapplication.

2The

threemisskills

forKED

arehypothesized

tobe

dueto

alack

ofcompleteseparatio

nof

theskullfrom

thevertebrae.

3The

twomisskills

forTED

weredueto

placem

enterrors

andpossibly

endof

thedayoperator

fatig

ue.

4The

threemisskills

forCO2weredu

eto

remov

alof

thehead

from

thedevice,toolow

gasconcentration,

andan

unknow

ncause.

5The

onemisskillforelectrical

euthanasia

was

dueto

inadequate

placem

entof

theelectrodenotin

thevent.

1028 JAPR: Research Report

Regulation (EC), 2009) for depopulation. Wheneuthanizing large birds such as broiler breedersor turkeys, manual CD may not be physicallypossible. The KED euthanasia method providesthe end user the means to cervically dislocate thebird. According to the manufacturer, minimaltraining is needed to perform the proper eutha-nizing technique and larger numbers of birds canbe euthanized without operator fatigue (model #:8152605, Clear View Enterprises, LLC., Tonti-town, AR).

Turkey Euthanasia Device–Captive Bolt

Captive bolt devices are a common methodfor the euthanasia of animals including poultryand stunning for slaughter of livestock. In aprevious study, the efficacy of the TED at pro-ducing immediate, fatal brain injury withoutrecovery followed by death was evaluated on253 male and female turkeys (Woolcott et al.,2018b). Efficacy was determined by evaluatingantemortem signs of insensibility (brainstemdisfunction) and clinical death, and postmortemassessment. Failures with the TED occurredbecause of previous head injury (because ofexcessive scabbing over the crown of the head),incorrect placement, or incorrect adapter selec-tion (too large spacing). Overall, the TEDeffectively caused immediate insensibilitythrough traumatic brain injury. In other studies,differences in successful euthanasia with captivebolt devices has been due to insufficient force(Finnie et al., 2003; Erasmus et al., 2010;Casey-Trott et al., 2013), incorrect placement(Finnie et al., 2003; Erasmus et al., 2010), andimproper restraint (Casey-Trott et al., 2014). Inthis work, the 2 birds not successfully eutha-nized using TED within 4 min were concludedto be due to incorrect placement by the operatoror operator fatigue. Utilization of the MBEAduring euthanasia should allow for properrestraint and can therefore improve a singleoperator’s ability to perform the captive bolteuthanasia method, with one hand holding thehead and the other positioning the TED. Afterchoosing the correct adapter to provide suffi-cient force for euthanasia and placing the birdinto the MBEA, the operator will have bothhands to ensure that the adapter is placed firmlyin the correct position for proper application.

BOYAL ET AL: POULTRY EUTHANASIA METHODS 1029

Carbon Dioxide Euthanasia

Although CO2 euthanasia has most often beenstudied as a method for mass depopulationrequired due to a disease outbreak, it is routinelyused on an individual bird basis to facilitate nec-ropsy for sample collection. In previous work, amobile modified atmosphere killing unit wasdeveloped for the purpose of on farm depopula-tion euthanasia of spent hens (Webster et al.,1996). This large unit had exterior dimensions of54 3 20 3 39.5 in (1.37 3 0.51 3 1.00 m) andrequired a 20 lb (9.07 kg) CO2 cylinder.

The mobile CO2 euthanasia device describedin this report provides a smaller unit withincreased portability and can be constructed andutilized by the end user without incurring sig-nificant costs of large equipment. In addition, asimilar commercially available CO2 euthanasiadevice for poultry has been recently developedand is commercially available (QC Supply,Schuyler, NE). One of the benefits of this sys-tem is that only the bird’s head is placed into aclear container providing the opportunity toobserve the bird’s behavior while being exposedto the CO2. The application length of timeneeded to euthanize the bird using the CO2

method (4 min) is longer than the other 3methods described in this article (15 s or less)and therefore distorts the assessment of time todeath; however, this length of time should notbe an issue if the system is used for occasional/infrequent individual bird euthanasia. To ensuresuccessful euthanasia using CO2, the operatorshould check each bird for signs of life (respi-ration) before removal of the head from the CO2

chamber.

Electrical Euthanasia

The procedure described for electricaleuthanasia ensures the passage of electricalcurrent through both the heart and the brain byplacing the electrodes in the vent and mouth ofthe bird. Electrical euthanasia (120 V Alter-nating Current) differs from electrical stunning(25 V pulsed Direct Current) in that a muchhigher voltage and alternating current waveform is applied during electrical euthanasiainducing cardiac fibrillation (Grandin, 2001).This method has the advantages of inducing

near instantaneous unconsciousness by passingcurrent through the brain, cardiac fibrillation bypassing current through the heart, and a com-plete absence of convulsions from the birdfollowing euthanasia. The statement byHernandez et al., 2019 that “These findingsconfirm the use of IV pentobarbital sodium asthe gold standard euthanasia method in matureand immature turkeys by causing immediatesigns of insensibility and death within 60 s orless after drug administration” implies theappropriateness of using electrical (alternatingcurrent) for euthanasia for poultry.

However, it still has a disadvantage of notbeing fully mobile due to the need for access toa 120 V AC power outlet. The use of electricaleuthanasia also requires an adequate knowledgeof electrical wiring and safety when purchasingand assembling the supplies and performingelectrical euthanasia. The added features of theindicator light and GFCI outlet both lend toenhancing operator safety when using thisdevice.

Euthanasia Method Costs

In addition to the need for effective eutha-nasia device options, the equipment needed forperforming euthanasia by the end user should becost effective. The supplies required to assemblethe MBEA totaled $154.01 (Table 2). The steelmedical cylinder cart was purchased for$125.14 and came equipped with the chain thatwas used to secure the traffic cone ($22.45). Aplastic 5-gallon bucket, $6.42 (Encore Plastics,Cambridge, OH), was placed below the trafficcone when blood loss occurs after euthanasiausing the KED and TED methods.

Each KED-C device was purchased from themanufacturer for $215.00 and the KED-T for$230.00. Once purchased, this method does notrequire any additional supply purchases forfuture use. The TED was purchased from themanufacturer for $1,418. The propane used topower the device was included, but futurereplacement propane is estimated at $14.18.

The supplies to assemble the CO2 apparatustotaled $146.92. The 20 oz CO2 tank was$30.95 and is approximately $4.50 to refill(Dick’s Sporting Goods, Coraopolis, PA). Eachtank fill is estimated to be adequate for at least

Table 2. Cost estimates for the mobile bird euthanasia apparatus (MBEA) and four alternative euthanasiamethods including the Koechner Euthanizing Device (KED), Turkey Euthanasia Device (TED), carbon dioxide(CO2), and electrical euthanasia.

Estimated costs for mobile bird euthanasia apparatusSteel Medical Cylinder Cart, Cylinder Capacity: 1, 500 lb. Load Capacity, 4800H x 19-1/200W (Dayton Electric,

Lake Forest, IL)$125.14

Traffic Cone—28" (J. J. Keller & Associates, Inc., Neenah, WI) $22.45Encore Plastics 50640 Industrial Plastic 5-Gallon Bucket (Encore Plastics, Cambridge, OH) $6.42Total $154.01

Estimated costs for KED euthanasiaKED-C (Clear View Enterprises, LLC, (CVE), Tontitown, AR) $215.00KED-T (Clear View Enterprises, LLC, (CVE), Tontitown, AR) $230.00

Estimated costs for TED euthanasiaTED (Bock Industries, Philipsburg, PA) $1,418.00Paslode 2-Pack Short Yellow Trim Fuel (subsequent with repeated use) (Paslode, Glenview, IL) $14.18Total $1,432.18

Estimated costs for CO2 euthanasiaLow-Pressure Series–CO2 Primary Double Gauge regulator (Micro Matic, Brooksville, FL) $93.0820 oz CO2 tank (Tippman Sports, Fort Wayne, IN) $30.95Paintball tank CGA 320 adapter (Interstate Pneumatics, Vista, CA) $8.7562-ounce plastic jar (recycled from home use) $0.00Ziploc Storage Bags Gallon (Ziploc, Racine, WI) $0.12Scotch Shipping Tape (3M, St. Paul, MN) $0.05B&K 3/8-in Barbed Barb x MIP Elbow Fitting (BK Products, Collierville, TN) $2.48Rollerflex Food Grade Crystal Clear Vinyl Tubing, 3/8-Inch ID x 1/2-Inch OD (10 Ft) (Rollerflex,

Elizabeth, NJ)$6.99

CO2 Tank Fill (Dick’s Sporting Goods, Coraopolis, PA) $4.50Total $146.92

Estimated costs for electrical euthanasiaLegrand radiant Gray 15-Amp Decorator GFCI Outlet (Legrand, West Hartford, CT) $13.98Legrand Pass & Seymour 15/20-Amp Toggle Commercial Light Switch (Legrand, West Hartford, CT) $2.98Sigma Electric 2-Gang Weatherproof Box 2-Gang Gray Metal Weatherproof Exterior New Work Standard

Square Exterior Electrical Box (Sigma Electric, Garner, NC)$8.58

100-Ft Outdoor Cord (ULINE, Pleasant Prairie, WI) $38.98Sigma Electric ProConnex 1/2-in Uf Cable Connector Conduit Fitting (Sigma Electric, Garner, NC) $2.386-Ft Indoor Cord (Value Tech Supply, Boca Raton, FL) $1.57Gardner Bender WingGard 2-Pack Metal Wire Connectors (Gardner Bender, New Berlin, WI) $4.18Sigma Electric 2-Gang Square Metal Weatherproof Electrical Box Cover (Sigma Electric, Garner, NC) $6.98Westek Automatic Plug-in Orbis LED Guide Light (Ace Hardware, Oak Brook, IL) $3.5915-Amp 3-Wire Grounding Single to Triple Orange Adapter (Leviton Manufacturing Company, Inc.,

Melville, NY)$4.98

Total $88.20

Abbreviations: ID, inside diameter; OD, outside diameter.

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50 uses. The CO2 tank requires a thread adapter($8.75) and a low-pressure double-gauge regu-lator at $93.08 which was connected to tubing at$6.99. The opposite end of the tubing wasconnected to an elbow fitting for $2.48 and wasattached to the clear plastic container that hadbeen recycled from general household use. Asingle gallon-sized bag ($0.12, Ziploc, Racine,WI) was secured to the lid with standardshipping tape ($0.05).

The total cost of the supplies for the electricaleuthanasia device was $88.20. The electricalbox was $8.58 and the GFCI outlet inside was$13.98, while the toggle switch was $2.98. Theoutdoor cord (30.5 m, 100 ft) connected to theelectrical box was $38.98, indoor cord $1.57,and the battery clips were $4.18. The single totriple adapter was $4.98 and the indicator lightwas $3.59. The weatherproof electrical boxcover on top of the device cost $6.98.

BOYAL ET AL: POULTRY EUTHANASIA METHODS 1031

To summarize, the costliest euthanasiamethods described in this report were thecommercially available devices, TED ($1,432)followed by KED-C ($215) KED-T ($230).Both the CO2 ($147) and electrical euthanasia($88) devices were designed and constructedfrom parts purchased online and through a localhardware store (Table 2).

Euthanasia Method Resources

Written and video resources for each eutha-nasia method are available either through themanufacturer or the Alabama CooperativeExtension System. A detailed manual for use ofthe Turkey Euthanasia Device is available on-line from Bock Industries (2016). In addition, aseries of videos are available addressing TEDuse and troubleshooting (Bock Industries,2019). User manuals for KED are availableonline from Clear View Enterprises and theAlabama Cooperative Extension System (ClearView Enterprises, 2018; Boyal et al., 2020a).Carbon dioxide and electrical euthanasia appa-ratus construction and use manuals are availablefrom the Alabama Cooperative ExtensionSystem (Boyal et al., 2020b,c). Video demon-strations of KED, carbon dioxide and electricaleuthanasia will be available from the AlabamaCooperative Extension System (personalcommunication).

CONCLUSIONS AND APPLICATIONS

1. With the development of the MBEA, all 4methods of euthanasia are suitable for use bya single operator and most of bird movementis restrained.

2. Using KED, TED, and CO2 provided anadvantage of complete portability in thepoultry house and being self-contained.

3. Electrical euthanasia is the least expensive anddoes not lead to postapplication convulsionsbut does require access to an electrical outletand a basic knowledge of electrical safety.

4. All four methods of euthanasia were usedsuccessfully to euthanize mature broilerbreeders and turkeys with minimal trainingfollowing the standard operating procedureswhile restrained in the MBEA.

ACKNOWLEDGMENTS

This work was supported by U.S. Poultryand Egg project #BRF011 and the USDA Na-tional Institute of Food and Agriculture, Hatch/Multi State project 1015896.

DISCLOSURES

The authors declare no conflict of interest.

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