Poultry Cannibalism: Prevention and Treatment

Cannibalism usually occurs when the birds are stressed by a poor management practice. Once becoming stressed, one bird begins picking the feathers, comb, toes and/or vent of another bird. Once an open wound or blood is visible on the bird, the vicious habit of cannibalism can spread rapidly through the entire flock. If you notice the problem soon after it begins, cannibalism can be held in check. However, if the problem is allowed to get out of hand it can be very costly. Cannibalism will lower the bird's value due to torn and damaged flesh and/or poor feathering and can result in poor welfare and high death losses. Once this habit gets out of hand, it is difficult to eliminate.

Because there are numerous reasons for outbreaks of cannibalism, it is important that cannibalism control be a part of your management program.

Cannibalism is usually caused by one or more conditions:

1. Overcrowding

Large breeds of chickens should be allowed:

• 1/4 sq. ft./bird for first 2 weeks
• 3/4 sq. ft./bird for 3-8 weeks
• 1.5 sq. ft./bird from 8 to 16 weeks of age
• 2 sq. ft./bird from 16 weeks on

Bantam chickens require half the space as large chickens.

With gamebirds, double the above recommendations. With pheasants, allow 25 to 30 sq. ft./bird after 12 weeks of age or use pick prevention devices like plastic peepers or blinders.

You should also verify whether there are any local regulations or requirements for certifying programs that may affect space requirements for your flock.

2. Excessive heat

When the birds become uncomfortably hot they can become extremely cannibalistic. Be sure to adjust the temperature as birds age according to available breed guidelines. A general recommendation is to brood young poultry at 95°F for the first week and then gradually decrease the temperature 5°F per week, until you reach 70°F or the outside temperature. The temperature should be measured at the height of the birds when standing directly under the heat source. Do not heat the entire brooding facility to the recommended temperature. Observe the birds to assess whether the temperature is adequate for your flock, and adjust as needed. Birds will tend to crowd together and/or huddle under the heat source if they are too cold or spread out away from each other and/or the heat source if they are too hot. Not decreasing the brooding temperature is a common mistake that leads to problems like cannibalism.

3. Excessive light

Extremely bright light or excessively long periods of light will cause birds to become hostile toward one another. Never use white light bulbs larger than 40 watts to brood fowl. If larger bulbs are required for heat, use red or infra-red bulbs. When raising birds 12 weeks of age or older, use 15 or 25 watt bulbs above feeding and watering areas. Never use Teflon-coated bulbs in poultry houses or coops as Teflon is toxic to birds. It is not recommended to provide birds with more than 16 hours of light per day. Constant light can be stressful to the birds.  Intermittent light for the first week of life is often recommended for commercial poultry.

4. Absence of feed or water or a shortage of feeder or waterer space

Pecking activity will increase if the birds have to fight for food and water, or if the birds are always hungry. Be sure that birds have free access to water and feed at all times. The pecking order determines which birds get to eat and when. When you have inadequate feeder space, birds at the lower end of the pecking order may never be allowed to eat.

5. Unbalanced diets

Extremely high energy and low fiber diets can cause birds to be extra active and aggressive. Feed lacking protein and other nutrients, particularly the amino acid Methionine, will also cause birds to pick feathers. Make sure you feed a diet balanced appropriately for the age and types of birds you are raising.

6. Mixing of different types, sizes, and colors of poultry

Mixing different ages and sizes of poultry or birds with different traits may promote pecking by disrupting the flock's normal pecking order. Never brood different species of poultry together in the same pen. Don't brood feathered leg birds, crested birds or bearded birds with birds without these traits. Curiosity can also start pecking. Toe pecking in the first few weeks is often started due to curiosity of the different colors or traits.

7. Slow feathering birds are most prone to cannibalism

Take extra precautions with slow feathering birds. Most cannibalism occurs during feather growth in young birds. Birds with slow feathering have immature tender feathers exposed for longer periods of time leaving them open to damage from pecking. Don't raise slow feathering birds with other poultry.

8. Abrupt changes in environment or management practices

For backyard or hobby flocks, if you plan to move young birds to a new location, it is best to move some of their feeders and waterers with them in order to help them adapt. When you change over to larger feeders and waterers it is helpful to leave the smaller equipment in the pen for a few days to help during the change.

For commercial flocks, the brood and/or grower housing and equipment should match the adult housing type and equipment as closely as possible. For example, layer pullets raised in cages should not be moved to a cage-free lay house.

9. Brightly lit nests or shortage of nesting boxes

Don't place bright lights near the nesting areas. If nest lights are used, they should be turned off as soon as birds begin to find the nests. A general recommendation is to allow 1 nest for every 5 hens; however, the exact ratio required may vary depending on the species, breed, and housing type. Vent pecking by layers is also a common problem.

9. Allowing cripples, injured or dead birds to remain in a flock

Birds will pick on crippled or dead birds in their pens because of the social order and curiosity. Once pecking starts it can quickly develop into a vicious habit. It is best to remove sick or injured birds from the flock as soon as possible. In some cases, it may be necessary to remove the aggressive bird(s) from the flock.

10. Introducing new birds to the flock

Anytime you add or remove birds from a flock you disrupt the pecking order of the flock. For backyard or hobby flocks, it is best to introduce any new birds into your pen by splitting the pen with a wire wall for at least a week to help the birds to get to know each other. Also, adding the birds to the perch at night can help. Always supervise new introductions to the flock and intervene if the pecking gets out of control and birds are getting hurt. It may take a week or more for flock to re-establish the new pecking order. Introducing new birds to your flock poses the risk of introducing disease to your flock. New birds should be quarantined for a period of at least 4 weeks prior to introducing them to the rest of your flock to monitor for signs of illness. 

11. Prolapse 

Prolapse can occur in very young or fat laying flocks. Prolapse is when the uterus stretches and tears and takes longer to properly return into the body cavity after the egg is laid. This is most common in young flocks that start laying too soon (prior to 20 weeks of age) or in fat layers. When the uterus is exposed for a period of time other birds will see it and pick at it out of curiosity. Once they pick at the uterus it bleeds, and the picking may quickly progress to cannibalism. If you start seeing blood streaks on the shell surface, birds in your flock may be experiencing prolapse. Properly managing how you bring your birds into production and proper feeding practices can prevent this problem. Fat birds will need to be put on a lower energy diet.

Additional preventive measures include:

1. Increase Space: Add perches to the barn or coop. For backyard or hobby flocks, allow the birds to use up their energy in an enclosed outside run. This will keep the birds busy and allow them to peck greens, ground and insects instead of other birds.
2. Add Enrichment: Provide toys to provide mental stimulation to birds. Placing colored or shiny items for the birds to pick at can draw attention away from pecking at other birds. Hanging shiny cans just above eye level can serve as a toy. Nutritional enrichment can provide increased fiber which keeps the birds' gizzard full and keeps the birds more content.  For backyard or hobby flocks, you can give the birds a large handful of fresh greens like clover grass or weeds, each day. Small parts of baled green leafy hay will also give the birds something to pick at. For commercial flocks, alfalfa cubes or haybales can be used.
3. Beak-treatment may be required for problem flocks. Obtain infra-red beak-treated birds from a hatchery. Contact your veterinarian to discuss whether beak trimming may be appropriate for older birds.  
4. Use of mechanical devices like plastic peepers or blinders in aggressive birds like gamebirds may be advisable.

Treatment for a cannibalism outbreak

Since cannibalism can be caused by several conditions, you may not be able to determine the exact cause of the problem. However, stress, no matter how slight, is usually the main factor.

To reduce stress: 

1. Try to correct any practices which may have lead to cannibalism.
2. Darken the facilities by adjusting light intensity.
3. Humanely remove any badly injured or overly aggressive birds.
4. Apply an "anti-peck" ointment or spray on any damaged birds to deter aggressors.
5. Lower the temperature a bit if possible.

Don't take chances! Make cannibalism control part of your management program and you will save a great deal of time and money. If you have tried these strategies and are still struggling with pecking in your flock, contact your veterinarian or Extension agent for additional assistance. 

Original author: Phillip J. Clauer, Penn State Extension and Department of Animal Science. Revised April 2023 by: Dr. Megan Lighty and Dr. Kayla Niel.