Effect of partial comb and wattle trim on pullet behavior and thermoregulation, 1

Effect of partial comb and wattle trim on pullet behavior and thermoregulation, 1 P. Y. Hester,,2 D. S. AL-Ramamneh, M. M. Makagon, and H. W. Cheng Department of Animal Sciences, Purdue University, West Lafayette, IN 47907; Department of Animal Science and Food Nutrition, Jerash Private University, Jerash 26150, Jordan; and USDA-Agricultural Research Service, Livestock Behavior Research Unit, West Lafayette, IN 47907. ABSTRACT The wattles and comb of chickens are important for thermoregulation allowing for heat exchange during high temperatures. These integumentary tissues are sometimes trimmed to prevent tears if caught on cage equipment and to also improve feed efficiency; however, the procedure itself could be painful to chicks. Our objective was to determine the effect of trimming the comb and wattles on behavior, BW, feed usage, and the surface temperature of pullets. The wattles and comb of Leghorns were partially trimmed at 21 d age (n = 6 cages, 13 chicks each) with another 6 cages serving as controls. Behaviors were recorded 3 times daily for 1 h starting at 0800, 1200, and 1500 using instantaneous scan sampling observations conducted every 5 min prior to, on the d of, and after the trim. Group BW at 21, 28, and 36 d age and the amount of feed used for 7 d beginning at 21 and 29 d age were measured per cage. At 1300 h on d before and after the trim, thermal images of the pullet s beak, comb, eye, wattle, and shank were randomly taken on 3 pullets/cage. Smaller proportions of trimmed chicks were eating and greater proportions were sitting on the d of the trim as compared to the controls with the opposite trend occurring on 4 d post-trim (treatment by age interaction, P = 0.03 and 0.0001, respectively). Standing behavior differed only on the d of the trim where smaller proportions of trimmed pullets stood as compared to intact controls (treatment by age interaction, P = 0.0002). Trimming the comb and wattles did not affect preening, running, BW, feed utilization, and the surface temperature of the pullet. The indices of behavior suggest that on the d of the trim, pullets may have experienced temporary distress, but they returned to normal behavior by 5 h post-trim with no long-term effect on BW, feed usage, or surface body temperature. Key words: trimmed wattle, trimmed comb, pullet, behavior, thermography 2015 Poultry Science 94:860 866 http://dx.doi.org/10.3382/ps/pev066 INTRODUCTION Some pullets at a young age are subjected to a comb trim, referred to as dubbing, and the wattles may be trimmed as well. The purpose of trimming the comb and wattles of caged chickens is to prevent damage to these integumentary tissues so that they do not become entrapped in cage equipment such as the feed delivery system (Williams et al., 1961; Card and Nesheim, 1972). Approximately 19 million pullets in the United C 2015 Poultry Science Association Inc. Received November 13, 2014. Accepted January 8, 2015. 1 The Islamic Development Bank provided financial support to D. S. AL-Ramamneh to visit Purdue University and conduct this study. The care and management of the animals were provided by F. A. Haan and B. D. Little, and the statistical advice was given by M. E. Einstein of Purdue University, West Lafayette, IN. Chicks were donated by Hy-Line Hatchery (Warren, IN). Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement of the USDA. The USDA is an equal opportunity provider and employer. 2 Corresponding author: phester@purdue.edu States are currently subjected to partial comb trim at a young age to improve feed efficiency and egg production as compared to intact hens (Davis and Hutto, 1955; Laurent and Carmon, 1959; Cole and Hutt, 1954; Williams et al., 1961). However, trimming the comb and wattles may impair the hen s ability to dissipate heat under conditions of high environmental temperature. Specifically, the superficial blood vessels of the comb and wattles vasodilate during hot weather allowing for heat transfer from the chicken to the environment through conductive heat loss. In addition to vasodilation of superficial vessels, chickens use other mechanisms for cooling themselves on a hot d such as panting (evaporative cooling), spreading their wings to take advantage of convective heat loss from the body, and drinking or splashing of water (Etches et al., 1995). There is little information in the scientific literature on the behavioral response of pullets subjected to a comb and wattle trim. Because other procedures such as the cauterization of chick s beaks with a hot blade caused short term pain (Gentle et al., 1991; 1997), it may be that chicks whose comb and wattles are 860

PULLET COMB AND WATTLE TRIM 861 trimmed may also experience pain. Animals experiencing pain demonstrate behavioral changes such as inactivity, eating disturbances, grooming, increased sleep, and social activities (Wall, 1979). Therefore, the objective of this study was to determine if trimming the comb and wattles of young chicks would alter feeding, standing, sitting, and other behaviors. In addition to behavioral indices, BW, feed usage, and the surface temperature of pullet chicks subjected to comb and wattles trim were evaluated. Our hypothesis was that the surgical trim of the comb and wattles would alter behaviors suggestive of distress or pain, but that the behavioral changes would be temporary with no longterm effect on BW, feed consumption, and surface body temperature as compared to intact controls. MATERIALS AND METHODS Procedures and experimental protocol were approved by the Purdue University animal care and use Figure 1. The effect of a 21-day-old trim of the comb and wattles as compared to intact controls on the proportion of chicks (a) eating, (b) standing, and (c) sitting 1.5 h before as well as 1.5 and 5 h after performing the trim. a,b At 1.5 h following the trim, least-square means lacking common superscripts differ (P < 0.05).

862 HESTER ET AL. Figure 2. (a) BW at 21, 28, and 36 d age and (b) feed usage from 21 to 28 and 29 to 36 d age of pullets whose comb and wattles were trimmed as compared to intact controls. committee. At 1-d age, 156 Hy-Line W36 beak trimmed hatchlings were placed in 12 pullet cages with 13 hens/cage in one room (3.66-m wide by 10.9-m long) of the Purdue University Poultry Research Farm. The pullet cages within the room were 3 decks high with double arrangement of cages with 6 rows cages per room. Only 2 out of the 6 rows of cages were used for the current study. The 2 rows were on the same side of the room and were the top 2 rows. Within a row of cages, 3 cages each were assigned either the trimmed or control treatments for a total of 6 cages/treatment. Stocking density was 286 cm 2 /chick with 4.7 cm feeder space/chick. Each cage provided water through 2 drip nipples that were raised gradually as the pullet grew. At 21 d age between 0938 and 1037 h, half of the pullets had their comb and wattles partially trimmed using surgical scissors as described in the Ag Guide (2010); whereas, the remaining half of the pullets served as controls with comb and wattle intact. At 12 wk age, one pullet was removed from each cage to prevent overcrowding so that stocking density became 310 cm 2 /chick with 5.1 cm feeder space per pullet. The extra chick per cage was placed in a spare pullet cage in the same room. Management and vaccination practices were used similar to industry standards. Pullets were fed a chick starter mash diet (ME 3,009 kcal/kg and 20% CP) from hatch to 3.9 wk age and a grower mash diet (3,005 kcal/kg and 18.6% CP) from 4 to 15.9 wk age. A step-down lighting regimen was used during the pullet phase where light h were gradually decreased from 22L:2D at 1 d age to 12L:12D by 9 wk age. Light intensity was 32 lux for the first wk age and reduced to 2.2 lux from 7 d to the end of the pullet phase at 17 wk age. Brooding was accomplished by regulating room temperature. Room temperature was kept at approximately 32 to 33 C (90 to 92 o F) the first 3 d of the chick s life followed by a decrease to 30 to 32 C (86 to 90 o F) from 4 to 7 d age. Afterwards, ambient temperature was gradually reduced each wk until a temperature of 21.1 C(70 o F) was reached at 36 d age which was then maintained until the end of the pullet phase. During the trim when the pullets were 21 d age, ambient temperature was 26 to 28 C (78 to 82 o F). Behavioral Observations Live observations of pullet behavior were carried out from 0800 to 0900, 1200 to 1300, and 1500 to 1600 h on all cages using instantaneous scan sampling at 5- min intervals at 3 d prior to, on the d of, and at 1, 2, 4, 6, 8, and 11 d post-trim. For each h of observation that was done, behavioral data were collected 12 times from each cage and averaged. Half of the cages housed trimmed pullets, whereas the other 6 cages contained intact controls. The numbers of pullets in each cage performing the activities of drinking, eating, standing, sitting, running, and preening were recorded, and the data expressed as a proportion of hens performing each of the activities. Other Measurements Group BW at 21, 28, and 36 d age and the amount of feed used for 7 d beginning at 21 and 29 d age were measured per cage. At 1300 h at 2, 1, 0, 1, 2, 3, 4, 5, and 6 d of the trim, 3 pullets/cage were photographed using an infrared image camera (FLIR Systems, Inc., Nashua, NH, Model No. FLIR-T62101). The pullets used for imaging were chosen randomly, and the photograph was taken at the eye level of the bird while the pullet remained in her cage. The distance between the camera and the pullet was 1 m. Light intensity was 2.2 lux. The settings for camera parameters were 60% for RH; 22 o C for reflected, apparent, as well as atmospheric temperatures; and 0.98 for emissivity. The mean temperature of selected body parts (beak, comb, left eye, wattle, and left tarsometatarsus or shank) was determined from the image of each photographed pullet using FLIR system software (Thermal CAM Research

PULLET COMB AND WATTLE TRIM 863 Figure 3. The proportion of pullet chicks observed eating (averaged across the 3 daily observation periods of 0800 to 0900, 1200 to 1300, and 1300 to 1600 h) before ( 3, 2, 1 d), the d of (0), and following (1, 2, 4, 6, 8, and 11 d) the trimming of the comb and wattles as compared to intact controls. a,b On the d the comb and wattles were trimmed (0 d) or 4 d post-trim, least-square means lacking common superscripts differ (P < 0.05) contributing to the treatment by d interaction (P = 0.03). Pro 2.10). Predefined geometric figures were used during the analysis using a polygon for the beak, comb, and wattle, a point for the eye, and a line for the tarsometatarsus. The temperatures for each body part per chick were averaged for each cage at each age. Statistical Analysis A randomized design was employed. Data collected over the age of the pullet were subjected to an ANOVA with repeated measures (Steel et al., 1997) using the MIXED model procedure of the SAS Institute (2008). The main fixed effects were treatment (trimming of the comb and wattles vs. intact controls) and age of the pullet. For behavioral measurements, h of the d was included in the statistical model as another repeated measurement. In addition, an ANOVA was conducted on behaviors on the d of trim with repeated measurements from 0800 to 0900 (1.5 h before the trim), 1200 to 1300 (1.5 h post-trim), and 1500 to 1600 (5 h post-trim) h when chicks were 21 d age. Arcsine square-root transformations were performed on the percentage data. Statistical trends were similar for both transformed and untransformed data; therefore, the untransformed leastsquare means and SEM were presented. The experimental unit was the pullet cage. For temperature readings, repeated measurements included the age of the pullets and the body part where temperature measurements were made. The Tukey Kramer test (Oehlert, 2000) was used to partition differences among treatment by age interaction means. RESULTS AND DISCUSSION On the d of the trim, the behavior of trimmed chicks differed from controls at 1.5 h following the treatment with no differences in behavior at 1.5 h prior to and 5 h following the trim resulting in a treatment by h interaction. Specifically, a lower proportion of trimmed pullets as compared to controls were eating (Figure 1a, P = 0.035) and standing (Figure 1b, P = 0.001), and a greater proportion were sitting (Figure 1c, P < 0.001) at 1.5 h post-trim. These behavioral changes suggest that the handling of chicks and the trimming of chick s comb and wattles caused short term pain or distress (Wall, 1979) but the effect was not long lasting. Beak trimming also causes changes in behavior suggestive of pain. Specifically, brown chicks of the ISA strain that were beak trimmed at 1 or 10 d age showed less activity and reduced feeding behavior when compared to beak intact control pullet chicks. These behavioral changes among beak trimmed birds dissipated after the first wk following trimming (Gentle et al., 1997). Three strains of egg-laying chickens originating from commercial stock demonstrated more inactive standing, couching, less pecking at feed, as well as less moving and preening for 3 wk following the trimming of the beak as compared to controls leading the authors to suggest that that the reduced activity following the beak trim was due to pain (Craig and Lee, 1990). The BW measured immediately before the trim at 21 d age and at weekly intervals thereafter for 2 wk (28 and 36 d age) was not affected by the trim treatment (Figure 2a). The temporary reduction in the proportion of chicks

864 HESTER ET AL. Figure 4. The proportion of pullet chicks observed (a) standing and (b) sitting before ( 3, 2, 1 d), the d of (0), and following (1, 2, 4, 6, 8, and 11 d) the trimming of the comb and wattles as compared to intact controls. Proportions were averaged across the 3 daily observation periods of 0800 to 0900, 1200 to 1300, and 1300 to 1600 h. a,b On the d the comb and wattles were trimmed (0 d) or 4 d post-trim (Figure 4b only), least-square means lacking common superscripts differ (P < 0.05) contributing to the treatment by d interaction (P = 0.0002 for standing and P = 0.0001 for sitting). consuming feed at 1.5 h post-trim (Figure 1a) had no long-terms effect on the amount of feed the chicks used from 21 to 28 and 29 to 36 d age (Figure 2b). A broader view of behavior from 3 d prior to 11 d post-trim also showed differences between trimmed and control chicks on the d of the trim (Figures 3 and 4). The 0 d of observation shown in Figures 3 and 4 is the average of the hourly observations made 1.5 h before, as well as 1.5 and 5 h post-trim. Overall, the proportion of chicks eating were less for trimmed than control pullets on 0 d, but trimmed chicks rebounded on d 4 post-trim with an increased proportion of chicks eating as compared to controls (Figure 3) which explains the lack of an effect of the trimming treatment on BW (Figure 2a) and feed utilization (Figure 2b). Not only was there a lower proportion of trimmed chicks eating on the d of the trim but also a lower proportion of chicks standing (Figure 4a) and a greater proportion sitting (Figure 4b) as compared to control pullets. These changes in behavior are all indices that the handling and trimming of comb and wattles caused immediate pain or distress. However, as noted in Figure 1 at 5 h post-trim, the recovery from any pain or distress was fast and persisted through 11 d post-trim (Figure 4). The decrease in the proportion of trimmed pullets sitting at 4 d post-trim (Figure 4b) was due to the increased proportion of pullets eating at the same age (Figure 3) again suggesting compensation for the short term pain or distress that the trim pullets may have experienced immediately post-trim. Preening (Figure 5a) and running (Figure 5b) were not affected by the trimming treatment. The temperature of surface body parts (beak, comb, eye, wattle, and shank) as measured through infrared

PULLET COMB AND WATTLE TRIM 865 Figure 5. The proportion of pullet chicks observed (a) preening and (b) running before ( 2, 1), the d of (0), and following (1, 2, 4, 6, 8, and 11 d) the trimming of the comb and wattles as compared to intact controls. Proportions were averaged across the 3 daily observation periods of 0800 to 0900, 1200 to 1300, and 1300 to 1600 h. thermography was not affected by the trimming treatment (P = 0.25, Figure 6) at any age of measurement (nonsignificant treatment by d interaction, P = 0.76). The left shank had a higher temperature (P < 0.0001, Figure 6) than the other body parts in both treatment groups perhaps due to the contact of the pullet s feet with the metal, wired cage floor leading to conductive heat transfer to the chick especially during brooding. The feet of birds play an important role in whole-body thermoregulation (Martineau and Larochelle, 1988, van Kampen, 1988). The feet and shanks of birds are effective conductors of heat because they are unfeathered, have little muscle tissue for heat production, and are richly vascularized. Blood flow rate through chicken s feet is highly variable and dependent on environmental temperate. Blood flow rates increased in chicken s feet with increased environmental temperatures (Hillman et al., 1982). Chickens can lose more than 25% of their metabolic heat through their feet at thermoneutral temperatures (Hillman and Scott, 1989). In conclusion, the indices of behavior suggest that on the d of the trim, pullets may have experienced temporary distress and pain, but they returned to normal behavior by 5 h post-trim with no long-term effect on BW, feed usage, or surface body temperature.

866 HESTER ET AL. Figure 6. The effect of trimming the comb and wattles of pullet chicks as compared to controls on the temperature of the beak, comb, left eye, wattle, and left shank as determined through infrared thermography. The least-square means ± SEM were averaged across 9 d of measurements from 2 d before to 11 d post-trim (n = 54 observations per least-square mean). The asterisk indicates that for both treatment groups, the temperature of the shank was higher than the other body parts (P < 0.0001). ACKNOWLEDGMENTS The Islamic Development Bank provided financial support to D. S. AL-Ramamneh to visit Purdue University and conduct this study. The care and management of the animals were provided by F. A. Haan and B. D. Little, and the statistical advice was given by M. E. Einstein of Purdue University, West Lafayette, IN. Chicks were donated by Hy-Line Hatchery (Warren, IN). Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply recommendation or endorsement of the USDA. The USDA is an equal opportunity provider and employer. REFERENCES Ag Guide. 2010. Chapter 9: Poultry. Page 119 in Guide for the Care and Use of Agricultural Animals in Research and Teaching, 3rd ed. Federation of Animal Science Societies, Champaign, IL. Card, L. E., and M. C. Nesheim. 1972. Chapter 4. Incubation and hatchery management. pp. 95 122 in Poultry Production, 11th ed. Lea and Febiger, Philadelphia, PA. Cole, R. K., and F. B. Hutt. 1954. The effect of dubbing on egg production and viability. Poult. Sci. 33:966 972. Craig, J. V., and H.-Y. Lee. 1990. Beak trimming and genetic stock effects on behavior and mortality from cannibalism in White Leghorn-type pullets. Appl. Anim. Behav. Sci. 25:107 123. Davis, G. T., and D. C. Hutto. 1955. Effects of dubbing on White Leghorn pullets. Poult. Sci. 34:1189 1190. Etches, R. J., T. M. John, and G. A. M. Verrinder-Gibbins. 1995. Behavioural, physiological, neuroendocrine and molecular responses to heat stress. Pages 31 66 in Poultry Production in Hot Climates. N. J. Daghir, ed. CAB Int., Cambridge, UK. Gentle, M. J., B. O. Hughes, A. Fox, and D. Waddington. 1997. Behavioural and anatomical consequences of two beak trimming methods in 1- and 10-d-old domestic chicks. Brit. Poult. Sci. 38:453 463. Gentle, M. J., L. N. Hunter, and D. Waddington. 1991. The onset of pain related behaviours following partial beak amputation in the chicken. Neurosci. Lett. 128:113 116. Hillman, P. E., and N. R. Scott. 1989. Energy budget of the chicken foot. J. Therm. Biol. 14:205 217. Hillman, P. E., N. R. Scott, and A. van Tienhoven. 1982. Vasomotion in chicken foot: Dual innervation of arteriovenous anastomoses. Am. J. Physiol. 242:R582 R590. Laurent, C. K., and J. L. Carmon. 1959. The effect of dubbing White Leghorn pullets. Poult. Sci. 38:139 141. Martineau, L., and J. Larochelle. 1988. The cooling power of pigeon legs. J. Exp. Biol. 136:193 208. Oehlert, G. W. 2000. Comparing models: The analysis of variance. Pages 44 52 in A First Course in Design and Analysis of Experiments. W. H. Freeman, New York, NY. SAS Institute. 2008. SAS Proprietary Software. Version 9.2. SAS Inst. Inc., Cary, NC. Steel, R. G. D., J. H. Torrie, and D. A. Dickey. 1997. Principles and Procedures of Statistics: A Biometrical Approach. 3rd ed. McGraw Hill, New York, NY. van Kampen, M. 1988. Effects of drinking water temperature and leg cooling on heat stress of laying hens (Gallus domesticus). J. Therm. Biol. 13:43 47. Wall, P. D. 1979. On the relation of injury to pain. Pain 6:253 264. Williams, C., D. L. Butler, and G. F. Godfrey. 1961. Dubbing (decombing) pullets pays. World s Poult. Sci. J. 17:280 286.