Performance and carcass characteristics of Delaware chickens in comparison with broilers

2014 Poultry Science Association, Inc. Performance and carcass characteristics of Delaware chickens in comparison with broilers B. A. McCrea, 1 A. F. Mills, K. Matthews, and J. Hutson Department of Agriculture and Natural Resources, Delaware State University, Dover 19901 Primary Audience: Extension Poultry Specialists, Extension Agents, Small Flock Owners DESCRIPTION OF PROBLEM In the last decade, interest in raising small flocks of chickens in the United States has increased. This is indicated by an increase in popular press articles in the United States [1], an increase in the number of magazines devoted to the topic of backyard poultry in the United States (e.g., Backyard Poultry, Chickens, Fowl SUMMARY The recent resurgence in the popularity of keeping small flocks of chickens has brought with it an interest in the production characteristics of heritage breeds of chicken. The Delaware breed was developed in the state of Delaware for meat production and is considered a heritage breed because it has long been passed over in favor of the Cornish cross. The definition of a heritage chicken breed is one that physically conforms to the standards of the American Poultry Association, mates naturally, has a long, productive outdoor lifespan, and a slow growth rate. Production information on raising meat Delawares is lacking, as recent research has focused on diet formulation and genetics for broiler production. This study was undertaken to determine the production efficiency of Delawares as compared with broilers in BW, feed intake, FCR, and carcass dressing percentage. Significant differences in BW were noted between broilers and Delawares throughout the study; this was evident even with chick weights. Delawares took 15 wk to reach the same live BW as that of a broiler at 6 wk. The feed intake was greater for the broilers over Delawares during their 6-wk grow-out. The Delawares required twice as much feed to reach the same BW as that of the broiler. Significant differences between the 2 breeds were observed with regard to FCR, the broilers being the more efficient breed. The Delawares had a significantly lower carcass dressing percentage, just under 65%, as compared with broilers, just over 68%. It is hoped that this information will aid producers of niche-market heritage chickens in their decision-making when considering this breed for meat production. Key words: heritage breed, Delaware, growth performance, broiler 2014 J. Appl. Poult. Res. 23 :586 592 http://dx.doi.org/10.3382/japr.2013-00843 USA) and a corresponding increase in magazine subscriptions [2], an increase in the number of books dedicated to raising small flocks [3 6], and an increase in the number of chick sales from small US hatcheries [7]. Correspondingly, several small-flock enterprises have an interest in raising heritage poultry breeds for meat production. To preserve many of these heritage chicken breeds, farmers must be able to confi- 1 Corresponding author: bmccrea@desu.edu

McCrea et al.: DELAWARE VERSUS BROILERS 587 dently grow and sell heritage chicken eggs or meat to justify raising the breed. Some research has been done on fast- versus slow-growing commercial hybrids [8 10], but very little research is available to assist growers in deciding upon which heritage breeds to raise. The lack of information about performance characteristics means that farmers have very little information to use to make pricing decisions or when creating a business plan. Heritage meat chickens are very slow-growing. Farmers do not know how long it takes to grow a flock to a final BW that is similar to that of a broiler. Farmers may underprice their product by basing prices on production data for commercial hybrids. The Delaware name and breed evolved from Barred Cross, to Indian River, and then to Delaware. Starting in the 1920s and 1930s, the newly emerging meat chicken industry bred pure lines of several different breeds of chicken. By 1935, efforts at crossing Barred Plymouth Rocks males with New Hampshire hens resulted in what was called Barred Cross chicks [11]. The Delaware chicken breed was developed in the 1940s on the Delmarva Peninsula as a result of the specific breeding efforts of George Ellis in Ocean View, Delaware. By emphasizing progeny testing with the crosses between Barred Plymouth Rock males and New Hampshire females, Ellis developed a breed that he named Indian River birds [12]. The name was later changed to Delaware and the breed was accepted into the American Poultry Association s Standard of Perfection in 1952 [13]. Shortly thereafter the breed fell out of favor as a meat bird, as the Cornish cross was further developed by the broiler industry. The breed is once again in demand; it is difficult to locate good breeding stock for meat production because the breed has been selected only for show. Little data about the growth performance of the breed is available after the 1940s and 1950s, as interest in the breed was greater for its unique plumage genetics [14, 15]. Given the significant changes and improvements to poultry diets, growth performance data are out of date in relation to the Delaware birds that are available for purchase today. The objective of the current study was 2-fold. The first objective was providing farmers with data on performance characteristics, feed efficiency, and carcass yield for Delawares in comparison to fast-growing broilers using modern feeds. The second objective was to determine the additional amount of time it would take to raise the Delawares until they achieved the same live BW as 6-wk-old fast-growing broilers. The production information may be used to write their business plans, make good management decisions, and to price product accurately. MATERIALS AND METHODS The Institutional Animal Care and Use Committee at Delaware State University approved all experiments involving live birds. The trial was conducted from March through June 2012. Birds and Housing Our study was a completely randomized design. One-day-old straight-run Delaware chicks were purchased from a hatchery [16] and, upon arrival, were weighed and randomly assigned to Delaware pen 1 or Delaware pen 2. Broiler eggs (Hubbard N99 Cobb 500) were obtained from a local hatchery [17] and incubated at Delaware State University. They were set to hatch on the same day as Delaware chick arrival. Upon hatch, chicks were weighed and randomly assigned to either broiler pen 1 or broiler pen 2. The chicks were housed in 10-10-ft floor pens with 30 birds per pen. Two replications were used for each breed of chicken. Each bird was allotted 3.3 ft 2 to emulate the average number of square feet per bird typically found on similar small broiler operations within the region. The bedding consisted of pine shavings. The birds were brooded at a temperature of 95 F in week 1, with temperatures dropped 5 F for each week thereafter until outdoor ambient temperatures were reached and the birds were fully feathered (Delawares) or the birds were processed (broilers). The Delaware chicken grew at a slower rate than the broilers, thus the average daily temperature that they experienced in the months of May and June was 66.7 and 72.2 F, respectively. The lighting program for the birds was 24 h of light for d 1 and then natural day lengths were used per the conditions that most small flock holders use on their operations. Broilers were raised to 6 wk of age and then processed. Delawares were raised to 15

588 JAPR: Research Report wk of age and then processed. Birds were processed using standard techniques as described in Contreras-Castillo et al. [18]. Carcass yield was determined by weighing the chicken before processing and then weighing them again after chilling. The heritage breed (Delaware) was allowed to continue to grow until the average live bird weight matched that of the broilers at the time of processing. Individual BW and feed intake, on a group basis, were recorded weekly. Mortality was recorded daily. Food and water were provided ad libitum during the study. Diets consisted of commercially available diets from Purina [19]. The starter diet, fed during the first 2 wk of the study, was Purina Honor Show Chow Broiler Complete with 26% CP. For the remainder of the study birds were fed Purina Flock Raiser Sunfresh with 20% CP. Statistical Analysis Data were analyzed by using SPSS software [20]. Body weight and feed consumption were calculated weekly, with the pen means being the experimental unit. The BW, feed consumption, FCR, carcass yield, and mortality were analyzed using an independent samples t-test. Significance was assigned at P 0.05. RESULTS AND DISCUSSION The performance of the Delawares was highly variable when compared with the uniformity of the broiler chicken performance. On the day that the chicks arrived, it was visually evident that the broiler chicks were of a larger size. This observation was confirmed by weighing the chicks. The broiler chicks weighed an average of 45.54 g, which was significantly larger (P < 0.01) than the Delaware s average weight of 35.31 g (Figure 1). These differences could be due to multiple variables (i.e., egg size, breeder flock age), given that a great deal more selection for meat production has occurred in the breeding broilers over the last several decades in comparison to Delawares. The chick BW in our study differs from similar work done by Schmidt et al. [21]. In Schmidt et al. [21], the 2 lines examined, Ross 708 and a New Hampshire Plymouth Rock cross, were not significantly different in BW on d 2 when they arrived at the start of the study. Figure 1. The average BW of chicks at the beginning of the study, presented as mean ± SD. Different letters (a,b) indicate a significant difference in BW between the 2 breeds of chicken (P < 0.01). The broilers were raised to 6 wk and their performance up to that age was compared with that of the Delawares. It took 2.5 times longer for the Delawares to achieve a similar final live BW (2.11 kg) as the broilers (2.16 kg). The grow-out yielded differences in average BW for the 2 breeds that were significant throughout the 6 wk (Figure 2; P < 0.01). Broilers grew to a weight that was 3.4 times heavier than that of the Delawares at 6 wk old. In addition, the Delawares took a full 15 wk to achieve a similar live BW as that of the broilers (Figure 2). In Schmidt et al. [21], research was terminated at 5 wk, so the length of time it took for the heritage line to reach the same market weight as that of the Ross 708 was not analyzed. However, their research concurred with ours in that the BW of the heritage line was significantly lower than that of the modern broiler. The overall BW gain for broilers and Delawares in our study was 2.12 and 2.07 kg, respectively (Table 1). Further research with additional replications should be able to reveal more information about the Delaware s capacity to gain BW steadily, although it is recognized that using straight-run chicks is a contributing factor for variation. It has long been established that the cross of Barred Plymouth Rock males with New Hampshire females produces a larger bird than their parent stock [22]. The slow-growing Delawares weighed less at 12 wk (1.665 kg) than that of the broiler strain being examined in

McCrea et al.: DELAWARE VERSUS BROILERS 589 Figure 2. The average BW (kg) for broilers and Delaware chickens from 1 to 15 wk of age (P < 0.01). Pooled SEM for broilers was 0.20 and for Delawares was 0.13. Different letters (a,b) indicate a significant difference in BW between the 2 breeds of chicken during each week (P < 0.01). the study by Essary et al. [22], which yielded a broiler that was 1.81 kg. This slower growth rate may indicate why today s Delaware has moved away from meat production and toward egg production characteristics. Similar past studies of male Barred Plymouth Rocks crossed with female New Hampshire chickens yielded larger male and female birds than Barred Plymouth Rock males crossed with White Plymouth Rock, Barred Plymouth Rock, White Leghorn, or Rhode Island Red females [23]. Small flock producers should keep this in mind as they choose breeds for their operations. Selection of the Delaware once again for meat production will likely be necessary to achieve the broiler weights seen during the 1950s. Feed intake for the broilers was consistently greater than that of the Delawares (Figure 3). The intake of feed for the 2 breeds is in concordance with the BW seen in Figure 2. The feed intake of the Delaware continued to increase, but it never reached the same levels of intake experienced by the broilers at the end of their grow out (Figure 3). The average amount of feed it took for a pen of broilers to reach market weight was 104.11 kg, whereas it took the Delawares 209.75 kg to reach approximately the same weight (Figure 4). These results are similar to work done by Fanatico et al. [24] in which a fast-growing broiler strain was compared with slower-growing broiler strains. In that study, the feed intake for the slower-growing birds was as- Table 1. Overall performance of broilers as compared with Delawares Item Broiler Delaware SEM P-value Overall BW gain (kg) 2.12 2.07 0.04 0.60 Overall FCR (kg:kg) 1.75 3.46 0.09 <0.01 Overall mortality (%) 11.8 3.45 0.58 0.02 Overall carcass yield (%) 68.08 64.61 0.41 <0.01

590 JAPR: Research Report sociated with the length of grow out. As the Delawares grow slower than the broilers, their feed intake will be greater. Based upon the amount of feed consumed by the 2 breeds and the price per bag of feed at the time of the trial, the cost to feed the broilers was $87.58 and the price to feed the Delawares was $170.13. It is estimated that it would cost 1.94 times more to feed the Delawares. As the cost of production for the Delawares, based on just the price of feed, was nearly 2-fold greater, farmers should price their final product accordingly. The overall FCR for broilers and Delawares in our study was 1.75 and 3.46, respectively (Table 1). No statistically significant differences were observed between the weekly FCR for the 2 breeds with the exception of wk 1, when the broilers had a more efficient FCR (Figure 5). This is likely due to the low number of replications, as a significant difference based on the overall FCR was noted. As the Delawares proceeded past wk 6, FCR continued to increase and then became highly variable toward the end of the trial. Schmidt et al. [21] also found that the FCR for the broiler was more efficient than that of the heritage line. Additionally, in Fanatico et al. [24], significant differences between fast-growing broilers and slower-growing broiler strains were also noted. A greater number of replications in future trials may be able to detect differences in the FCR between broilers and Delawares. Given the price of feed for many small- or niche-market flock owners, it is important to note that the efficient conversion of the feed to meat will yield a product of lower cost. As it stands, the Delaware breed will require further refinement to improve the FCR. It is also important to note that further research with more replications will likely further elucidate more information on the growth performance and feed efficiency of the Delaware breed. The weight of the broiler carcasses was significantly heavier (P = 0.009) than that of the Delaware carcasses. Despite being processed at the same live weight as that of the broilers, it appears that the Delawares were inefficient at developing muscle on the carcass and more efficient at building bones and internal organs. It is hoped that our study can be repeated in the future and that bone length and parts yield can be measured. The average weight for the broiler carcasses was 1.48 ± 0.23 kg, whereas the aver- Figure 3. The average weekly feed intake (kg) for the 2 breeds from wk 1 to 15. Pooled SEM for broilers was 2.33 and for Delawares was 1.48. Different letters (a,b) indicate a significant difference in feed intake between the 2 breeds of chicken (P < 0.05).

McCrea et al.: DELAWARE VERSUS BROILERS 591 Figure 4. The cumulative feed intake (kg) for the 2 breeds during wk 1 to 15. Pooled SEM for broilers was 17.94 and for Delawares was 11.34. Different letters (a,b) indicate a significant difference in cumulative feed consumption between the 2 breeds of chicken (P < 0.05). age weight for the Delaware carcasses was 1.36 ± 0.24 kg. A significant difference (P < 0.01) between the 2 breeds of chicken with regard to their dressing percentage was seen. The dressing percentage for the broilers was 68.08 ± 3.64% (Table 1) and the Delaware dressing percentage was lower, at 64.61 ± 4.65%. These data are in concordance with work done by Fanatico et al. Figure 5. The FCR (kg:kg) for 2 breeds during wk 1 to 15. Pooled SEM for broilers was 0.46 and for Delawares was 0.29. Different letters (a,b) indicate a significant difference in FCR between the 2 breeds of chicken (P < 0.05).

592 JAPR: Research Report [24], in which the faster-growing broilers had a greater percent carcass yield than that of the slower-growing broiler strains. It is hoped that in future studies on the Delaware, measurement on the femur, tibia, and metatarsus bones will yield data that provide insight into the part development for this slower-growing breed. During the 6-wk period of comparison between the 2 breeds, the Delawares had significantly less mortality (1.6%; P < 0.01) than the broilers (11.8%; Table 1). This could perhaps indicate that the Delawares are more suited to the housing and management conditions associated with smaller-scale poultry production; however, the quantity of birds used in our study was relatively small. CONCLUSIONS AND APPLICATIONS 1. Broilers grew to a final BW of 2.11 kg 2.5 times faster than that of the Delaware chickens. 2. For Delawares to be raised to a similar live BW as that of a broiler it will take approximately 15 wk. 3. Body weight, feed intake, FCR, carcass size, and dressing percentage were found to be superior in broilers as compared with the Delawares. REFERENCES AND NOTES 1. Orlean, S. 2009. The it bird. The New Yorker Magazine. Accessed May 17, 2013. http://www.newyorker.com/ reporting/2009/09/28/090928fa_fact_orlean?printable=true &currentpage=all. 2. Belanger, E. 2012. Personal communication. Backyard Poultry Magazine, Medford, WI. 3. Litt, R., and H. Litt. 2011. A Chicken in Every Yard: The Urban Farm Store s Guide to Chicken Keeping. Ten Speed Press, Berkeley, CA. 4. Schneider, A. G., and B. McCrea. 2011. The Chicken Whisperer s Guide to Keeping Chickens: Everything You Need to Know and Didn t Know you Needed to Know about Backyard and Urban Chickens. Quarry Publishing Group, Beverly, MA. 5. Foreman, P. 2010. City Chicks: Keeping Microflocks of Chickens as Garden Helpers, Compost Makers, Biol.-Recyclers, and Local Food Producers. Good Earth Publications Inc., Buena Vista, VA. 6. Willis, K., and R. Ludlow. 2009. Raising Chickens for Dummies. For Dummies, Indianapolis, IN. 7. Stromberg, C. 2011. Personal communication. Stromberg s Chicks and Game Birds Unlimited, Pine River, MN. 8. Wang, K. H., S. R. Shi, T. C. Dou, and H. J. Sun. 2009. Effect of a free-range raising system on growth performance, carcass yield, and meat quality of slow-growing chicken. Poult. Sci. 88:2219 2223. 9. Fanatico, A. C., P. B. Pillai, P. Y. Hester, C. Falcone, J. A. Mench, C. M. Owens, and J. L. Emmert. 2008. Performance, livability, and carcass yield of slow- and fastgrowing chicken genotypes fed low-nutrient or standard diets and raised indoors or with outdoor access. Poult. Sci. 87:1012 1021. 10. Fanatico, A. C., P. B. Pillai, L. C. Cavitt, C. M. Owens, and J. L. Emmert. 2005. Evaluation of slower-growing broiler genotypes with and without outdoor access: growth performance and carcass yield. Poult. Sci. 84:1321 1327. 11. Tomhave, A. E. 1951. The Poultry Industry in Delaware During the Last 50 Years (1900 1950). Delaware Notes 24:129 143. 12. Gordy, J. F. 1974. Broilers: Fifty Year Old Meat Industry Present Outstanding Picture of Specialization in American Poultry History 1823 1973. American Printing and Publishing Inc., Madison, WI. 13. American Poultry Association Inc. 2010. American class. Pages 62 63 in American Standard of Perfection. American Poultry Association, Burgettstown, PA. 14. Jaap, R. G. 1955. Shank color and barred plumage in Columbian-colored chickens. Poult. Sci. 34:389 395. 15. Hess, C. W., T. C. Byerly, and M. A. Jull. 1941. The efficiency of feed utilization by barred plymouth rock and crossbred broilers. Poult. Sci. 20:210 216. 16. Murray McMurray Hatchery, Webster City, IA. 17. Allen s Hatchery, Seaford, DE. 18. Contreras-Castillo, C., A. A. Pinto, G. L. Souza, N. J. Beraquet, A. P. Aguiar, K. M. V. A. B. Cipolli, M. I. Mendez, and E. M. Ortega. 2007. Effects of feed withdrawal periods on carcass yield and breast meat quality of chickens reared using an alternative system. J. Appl. Poult. Res. 16:613 622. 19. Purina, St. Louis, MO. 20. SPSS for Windows, release 17.0, SPSS, Inc., Chicago, IL. 21. Schmidt, C. J., M. E. Persia, E. Feierstein, B. Kingham, and W. W. Saylor. 2009. Comparison of a modern broiler line and a heritage line unselected since the 1950s. Poult. Sci. 88:2610 2619. 22. Essary, E. O., G. J. Mountney, and O. E. Goff. 1951. Conformation and performance in standard bred and crossbred broilers. Poult. Sci. 30:552 557. 23. Glazener, E. W., and W. L. Blow. 1951. Topcross testing for broiler production. Poult. Sci. 30:870 874. 24. Fanatico, A. C., P. B. Pillai, L. C. Cavitt, C. M. Owens, and J. L. Emmert. 2005. Evaluation of slower-growing broiler genotypes grown with and without outdoor access: Growth performances and carcass yield. Poult. Sci. 84:1321 1327.