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The Science Behind the Better Chicken Commitment

The Better Chicken Commitment is informed by over 150 independent scientific studies published in academic journals.

A chicken

How were the welfare standards in the Better Chicken Commitment developed?

The Better Chicken Commitment is informed by over 150 independent scientific studies published in academic journals, including Animals, Poultry Science, Animal Behavior, and The Veterinary Journal.

This body of research covers each of the Better Chicken Commitment components (litter, lighting, stocking density, environmental enrichments, slaughter, and breed) and the wide range of welfare outcomes they influence (including walking ability, activity level, capacity to express natural behavior, presence of skin lesions and muscular myopathies, and mortality).

More information can be found in the complete US Broiler Chicken Welfare whitepaper.

Breed

  • Conventional breeds have a mortality rate over two times higher than breeds included in the Better Chicken Commitment.[1] [2] [3] Lower mortality rates help to mitigate waste in broiler production, preventing needless expenditure on birds that won’t survive to slaughter.
  • The vast majority of conventional breeds produce meat with visible muscular myopathies, including white striping (92.4%) and woody breast (42.4%), which lower meat quality. Up to 37% of conventional breeds suffer from lameness (the inability to walk properly), as opposed to only 10% of the slower-growing breeds.[4] Using exclusively Better Chicken Commitment-approved breeds can help mitigate this.[5] As with mortality rates, muscular myopathies contribute to excess waste by rendering chicken meat unsuitable for sale.

Environment

  • Housing chickens at high stocking densities is a common practice in the broiler industry and has been shown to cause reduced air and litter quality.[6] [7] [8] [9]
  • Damp and dirty litter increases the risk of ammonia burns on the chicken’s skin, including breast blisters, hock burns, and footpad dermatitis.[10] [11]
  • Broiler houses are usually barren environments with no multisensory enrichments allowing chickens to express natural behavior, contributing to the low behavioral activities of broilers.[12]
  • Broilers in standard production systems are reared in low lighting conditions during the day, which results in footpad lesions,[13] [14] poor leg health,[15] and eye abnormalities.[16] [17] [18] [19] At night time, broilers are typically not offered a continuous period of rest, which can disrupt the behavioral rhythms of broiler flocks,[20] increase fearfulness,[21] [22] [23] [24] impact normal ocular development,[25] and decrease activity and comfort behaviors.[26] [27]
  • The Better Chicken Commitment requirements include reducing the maximum stocking density to 6 lbs/sq. ft., providing a minimum of 8 hours of continuous light (≥50 lux) and 6 hours of continuous darkness daily, providing a litter depth of at least three inches, and adding enrichments to encourage the expression of natural behaviors. These requirements have been shown to improve skin condition, leg and foot health, and decrease mortality—all of which can help reduce the environmental impact of conventional meat production.[28] [29] [30] [31] [32] [33]

Slaughter

  • Electric water-bath stunning, common in conventional poultry slaughterhouses, is not effective for all birds. In 2020, almost half a million birds were found by the USDA to have died for unintended reasons, meaning they were possibly alive and conscious when entering the scald tank.[34] Chickens subject to electric water bath stunning also have a higher rate of muscle hemorrhaging, broken bones, and carcass damage than those stunned with CO2.[35] [36]
  • Controlled atmosphere stunning eliminates the need for live handling, shackling, and inversion of conscious chickens and should ensure chickens are fully unconscious at neck cutting and dead by the time they reach the scalding tank.[37] It has also been shown to reduce contamination risk for slaughterhouse workers and poultry meat.[38] [39]

More information on the science behind the Better Chicken Commitment can be found in the US Broiler Chicken Welfare whitepaper, which offers a deep dive into the science supporting the Better Chicken Commitment.

  1. Dixon, L. M. Slow and steady wins the race: The behaviour and welfare of commercial faster growing broiler breeds compared to a commercial slower growing breed. PLoS one 15, e0231006 (2020). ↩︎

  2. Rayner, A.C., Newberry, R.C., Vas, J. et al. Slow-growing broilers are healthier and express more behavioural indicators of positive welfare. Sci Rep 10, 15151 (2020). ↩︎

  3. Abeyesinghe, S. M., Chancellor, N. M., Moore, D. H., Chang, Y. M., Pearce, J., Demmers, T., & Nicol, C. J. Associations between behaviour and health outcomes in conventional and slow-growing breeds of broiler chicken. Animal 15, 100261 (2021). ↩︎

  4. Dixon, L. M. Slow and steady wins the race: The behaviour and welfare of commercial faster growing broiler breeds compared to a commercial slower growing breed. PLoS one 15, e0231006 (2020). ↩︎

  5. Kuttappan, V. A., Owens, C. M., Coon, C., Hargis, B. M., & Vazquez-Anon, M. Incidence of broiler breast myopathies at 2 different ages and its impact on selected raw meat quality parameters. Poult. Sci. 96, 3005-3009 (2017). ↩︎

  6. Meluzzi, A., Fabbri, C., Folegatti, E. & Sirri, F. Effect of less intensive rearing conditions on litter characteristics, growth performance, carcase injuries and meat quality of broilers. Br. Poult. Sci. 49, 509–515 (2008). ↩︎

  7. Estevez, I. Density allowances for broilers: where to set the limits? Poult. Sci. 86, 1265–1272 (2007). ↩︎

  8. Guardia, S. et al. Effects of stocking density on the growth performance and digestive microbiota of broiler chickens. Poult. Sci. 90, 1878–1889 (2011). ↩︎

  9. Farhadi, D., Hosseini, S. M. & Dezfuli, B. T. Effect of house type on growth performance, litter quality and incidence of foot lesions in broiler chickens reared in varying stocking density. Journal of BioScience & Biotechnology 5, 69–78 (2016). ↩︎

  10. Haslam, S. M. et al. Factors affecting the prevalence of foot pad dermatitis, hock burn and breast burn in broiler chicken. Br. Poult. Sci. 48, 264–275 (2007). ↩︎

  11. de Jong, I., Berg, C., Butterworth, A. & Estevéz, I. Scientific report updating the EFSA opinions on the welfare of broilers and broiler breeders. EFSA Supporting Publications 9, (2012). ↩︎

  12. Riber, A.B., van de Weerd, H.A., de Jong, I.C., Steenfeldt, S. Review of environmental enrichment for broiler chickens. Poult. Sci. 97, 378–396. (2018). ↩︎

  13. Deep, A., Schwean-Lardner, K., Crowe, T. G., Fancher, B. I. & Classen, H. L. Effect of light intensity on broiler production, processing characteristics, and welfare. Poult. Sci. 89, 2326–2333 (2010). ↩︎

  14. Deep, A., Raginski, C., Schwean-Lardner, K., Fancher, B. I. & Classen, H. L. Minimum light intensity threshold to prevent negative effects on broiler production and welfare. Br. Poult. Sci. 54, 686–694 (2013). ↩︎

  15. Blatchford, R. A., Archer, G. S. & Mench, J. A. Contrast in light intensity, rather than day length, influences the behavior and health of broiler chickens. Poult. Sci. 91, 1768–1774 (2012). ↩︎

  16. Deep, A., Schwean-Lardner, K., Crowe, T. G., Fancher, B. I. & Classen, H. L. Effect of light intensity on broiler production, processing characteristics, and welfare. Poult. Sci. 89, 2326–2333 (2010). ↩︎

  17. Deep, A., Raginski, C., Schwean-Lardner, K., Fancher, B. I. & Classen, H. L. Minimum light intensity threshold to prevent negative effects on broiler production and welfare. Br. Poult. Sci. 54, 686–694 (2013). ↩︎

  18. Blatchford, R. A., Archer, G. S. & Mench, J. A. Contrast in light intensity, rather than day length, influences the behavior and health of broiler chickens. Poult. Sci. 91, 1768–1774 (2012). ↩︎

  19. Blatchford, R. A. et al. The effect of light intensity on the behavior, eye and leg health, and immune function of broiler chickens. Poult. Sci. 88, 20–28 (2009). ↩︎

  20. Schwean-Lardner, K., Fancher, B. I., Laarveld, B. & Classen, H. L. Effect of day length on flock behavioural patterns and melatonin rhythms in broilers. Br. Poult. Sci. 55, 21–30 (2014). ↩︎

  21. Bayram, A. & Özkan, S. Effects of a 16-hour light, 8-hour dark lighting schedule on behavioral traits and performance in male broiler chickens. J. Appl. Poult. Res. 9, 263-273 (2010). ↩︎

  22. Sanotra, G. S., Lund, J. D., & Vestergaard, K. S. Influence of light-dark schedules and stocking density on behaviour, risk of leg problems and occurrence of chronic fear in broilers. Br. Poult. Sci. 43, 344-354 (2002). ↩︎

  23. Zulkifli, I., Rasedee, A., Nor Syaadoh, O., Che Norma M.T. Daylength Effects on Stress and Fear Responses in Broiler Chickens Asian-Australas J Anim Sci. 11, 751-754. (1998). ↩︎

  24. Onbaşılar, E., Erol, H., Cantekin, Z., Kaya, Ü. Influence of Intermittent Lighting on Broiler Performance, Incidence of Tibial Dyschondroplasia, Tonic Immobility, Some Blood Parameters and Antibody Production. Asian-Australas J Anim Sci. 20, 550-55 (2007). ↩︎

  25. Li, T., Howland, H.C., Troilo, D. Diurnal illumination patterns affect the development of the chick eye. Vision Res. 40, 2387-93. (2000). ↩︎

  26. Bayram, A. & Özkan, S. Effects of a 16-hour light, 8-hour dark lighting schedule on behavioral traits and performance in male broiler chickens. J. Appl. Poult. Res. 9, 263-273 (2010). ↩︎

  27. Schwean-Lardner, K., Fancher, B. I. & Classen, H. L. Impact of daylength on the productivity of two commercial broiler strains. Br. Poult. Sci. 53, 7–18 (2012). ↩︎

  28. Haslam, S. M. et al. Factors affecting the prevalence of foot pad dermatitis, hock burn and breast burn in broiler chicken. Br. Poult. Sci. 48, 264–275 (2007). ↩︎

  29. Sanotra, G. S., Lund, J. D., & Vestergaard, K. S. Influence of light-dark schedules and stocking density on behaviour, risk of leg problems and occurrence of chronic fear in broilers. Br. Poult. Sci. 43, 344-354 (2002). ↩︎

  30. Schwean-Lardner, K., Fancher, B. I. & Classen, H. L. Impact of daylength on the productivity of two commercial broiler strains. Br. Poult. Sci. 53, 7–18 (2012). ↩︎

  31. Schwean-Lardner, K. et al. Effect of day length on cause of mortality, leg health, and ocular health in broilers. Poult. Sci. 92, 1–11 (2013). ↩︎

  32. Ononiwu, J. C., Thomson, R. G., Carlson, H. C., & Julian, R. J. Studies on effect of lighting on “sudden death syndrome” in broiler chickens. The Canadian Veterinary Journal 20, 74 (1979). ↩︎

  33. Hassanzadeh, M., Bozorgmerifard, M. H., Akbari, A. R., Buyse, J., & Decuypere, E. Effect of intermittent lighting schedules during the natural scotoperiod on T3-induced ascites in broiler chickens. Avian Pathology 29, 433-439 (2000). ↩︎

  34. USDA. Poultry Slaughter 2020 Summary. USDA, National Agricultural Statistics Service (2021). Available at: https://downloads.usda.library.cornell.edu/usda-esmis/files/pg15bd88s/f1882d39g/j6731z19s/pslaan21.pdf. ↩︎

  35. Mohan Raj, A.B., Gregory, N.G., Austin, S.D. Prevalence of broken bones in broilers killed by different stunning methods. Vet Rec. 127, 285-7 (1990). ↩︎

  36. Kang, I.S., Sams, A.R., Bleedout efficiency, carcass damage, and rigor mortis development following electrical stunning or carbon dioxide stunning on a shackle line, Poult. Sci. 78, 139-143 (1999). ↩︎

  37. Shields, S. J. & Raj, A. B. M. A critical review of electrical water-bath stun systems for poultry slaughter and recent developments in alternative technologies. J. Appl. Anim. Welf. Sci. 13, 281–299 (2010). ↩︎

  38. Mulders, M.N., et al. Prevalence of livestock-associated MRSA in broiler flocks and risk factors for slaughterhouse personnel in The Netherlands. Epidemiol Infect. 138, 743-55. (2010). ↩︎

  39. Seliwiorstow, T., Baré, J., Berkvens, D., Van Damme, I., Uyttendaele, M., De Zutter, Z. Identification of risk factors for Campylobacter contamination levels on broiler 226, 26-32 (2016). ↩︎

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