Profits in the poultry industry depend on feed conversion and rapid growth. In 1957, broilers weighed about 1 kg at 56 days old, whereas today they reach around 4 kg at the same age.
Breeding for increased appetites and fast growth has resulted in meatier birds. But these heavier birds experience health complications and decreased reproduction.
“Hens for broiler production must carry the genes for increased appetite, growth and high meat yield, yet also have a lighter bodyweight that supports a longer lifespan and fertilized egg production,” said University of Arkansas graduate student Allison Weaver during a virtual symposium on poultry welfare sponsored by the Poultry Extension Collaborative.
Feed restrictions are used to maintain the lower bodyweight required for broiler breeders. Weaver’s research explored how feed restrictions affect bird welfare.
Qualitative versus quantitative feed restriction
Weaver explained that feed restrictions are either quantitative or qualitative. Quantitative restrictions, which reduce the amount of feed offered each day, can involve frequent small feedings every day or skipping a day of feeding.
In skip-a-day (SAD) feeding, birds are fed every other day or follow an equivalent schedule in which they are fed some days and not others. Qualitative restrictions involve providing feed that contains fewer calories. Fiber, such as soy hulls, is often added. Appetite suppressants can also be added, but Weaver pointed out that this isn’t a common practice in the poultry industry.
“Qualitative feed restrictions alone are not enough to control bodyweight. Better results are achieved when combined with quantity restrictions,” Weaver stated.
Behavior changes in feed-restricted birds
How do these birds, which have been selected for increased appetites, respond when they have less food than they prefer? Weaver looked for abnormal, repetitive and redirected oral behaviors indicating discomfort, frustration or agitation. These behaviors include increased foraging, feather pecking and pecking at the drinking line.
Her research involved feed restriction in 950 Cobb hens from 0 to 33 weeks of age, housed in pens with 16 birds each. The hens were either fed every other day or given small amounts of feed frequently throughout the day. They had either unlimited access to water or had water restricted, with the water turned off for 3 hours daily.
Weaver observed behaviors for 20 minutes at 16 and 22 weeks of age during three periods each day: 1.5 hours after feeding, at the start of water restriction at 12 p.m. and at the end of water restriction. She also measured the water consumption of normally fed birds at 4, 10, 16 and 22 weeks of age.
The SAD birds drank less 1.5 hours after feeding but drank more at both afternoon time points. Weaver suggested this could be because SAD birds need more time to eat their larger portion of feed. The SAD birds drank the most at 22 weeks old. Overall, SAD hens drank 150% more than birds fed daily. However, Weaver noted that it was difficult to tell whether water was actually consumed or just used.
SAD birds showed more water-line pecking without water use, along with increased preening and dust bathing. These birds also rested and pecked their feathers more than those fed daily.
Birds fed a restricted amount daily were more active before feeding and displayed more anticipatory behaviors. Hens on higher-fiber diets drank less but pecked more at the drinking lines.
Weaver noted that the increased water-line pecking was evident in wet litter, and this spillage could lead to health problems such as foot pad lesions.
All groups of feed-restricted birds exhibited chronic hunger behaviors. “Their abnormal behaviors indicate a negative welfare status,” she said.
Overcoming negative welfare status
Weaver proposed three options to overcome the negative welfare status:
- Precision feeding
- Scatter feeding
- Increasing feeding frequency
However, she said that precision feeding, which requires each bird to be fed to its ideal weight, isn’t a scalable option for the industry. “Scatter feeding, while it does enable the expression of foraging behavior, still leaves birds hungry. And increasing the frequency of feeding with small portion sizes will also leave birds hungry.”
Weaver noted that there are some positive health benefits of feed restrictions, but overall, feed restrictions negatively affect the birds’ welfare. However, she noted that restricting feed is necessary to maintain production.
“This study didn’t provide a clear answer on how to improve the welfare of birds that are feed-restricted,” Weaver said, adding that “Varying feed quality and quantity might offer some improvements, but birds still show signs of chronic hunger.” She pointed out that different flocks may respond differently, and a solution or combination of solutions could work well for some birds but not others.
Weaver concluded that, “Maintaining poultry welfare and mitigating stressors while restricting calories will require more research.”
