Conventional egg-laying cages were developed partly to decrease the risk of diseases, but that may increase in more open housing
OLDS, Alta. — Egg Farmers of Canada says it is meeting consumer demand for eggs from cage-free barns by phasing in changes to barn designs.
However, those changes come with consequences.
The organization announced in February its members hope to switch to larger, roomier cages, free run aviaries and free range systems for hens by 2036.
But moving birds from cramped cages to larger facilities can lead to more injuries or deaths from smothering and diseases, University of Guelph researcher Alexandra Harlander told Alberta Farm Animal Care’s annual meeting in Olds March 23.
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“It may never be possible to provide an ideal system because increasing their opportunities for more natural freedom may un-avoidably increase the risks of certain diseases or injuries.”
Researchers are looking at the physical and psychological health of birds under various systems.
Conventional cages were developed to increase productivity and decrease the risk of diseases. The consequences were that the birds had little freedom to move, and public pressure started to mount against what seemed like factory production conditions.
Furnished and enriched cages offer more room, perches and scratching areas with fewer birds in a space.
Non-cage systems may have thousands of birds in one henhouse. They have access to open space with nest boxes, perches water and food.
Fifty percent of the eggs produced in the United Kingdom come from free range systems. They offer outdoor and indoor housing in which birds can roam outside, but protection is offered against the elements.
Studies show death rates are generally higher in non-cage systems, but good management can reduce flock mortalities.
“In all housing systems, there are problems with damaging be-haviour,” she said.
The primary cause of death is feather pecking, which can lead to cannibalism. It occurs when one bird plucks the feathers from another and eats the feathers. One bird may start and the rest join in.
A British study found that nearly 80 percent of birds suffered from feather pecking.
“We assume it is a re-directing behaviour from food pecking, ground pecking or pecking during dust bathing. It is a multi-factoral problem,” she said.
Stress and diet may contribute to the problem.
Pullets need to adjust to low levels of disturbance, and workers might try wearing different coloured clothes, talking to them or walking with them. Fearful birds are more at risk to peck.
High fibre diets reduce the risk of feather pecking because the birds spend more time eating rather pecking each other.
Straw bales may help pullets find other things to do, and access to outdoor areas is also beneficial.
Feather pecking decreased after an experiment at the U of G added 10 percent chopped feathers to the diet.
A range of weights within the flock seemed to increase pecking.
Beak trimming of chicks is controversial and is banned in some countries. Trimming cuts living tissue, which causes acute and chronic pain, but the chickens peck less.
“You don’t address the cause of feather pecking but instead address the symptoms,” she said.
Another problem confronting chickens is exposure to viral, bacterial and parasitic infections. Better vaccination can reduce viruses and parasites in pen housing systems, but there are more bacterial infections.
Birds in non-caged systems have problems with foot pad dermatitis. Up to 40 percent of the birds have sores on their feet, which impair their ability to walk.
Keel bone injuries are a significant welfare problem in the laying industry. It is the equivalent to a breast bone in a bird.
Caged birds may have weak bones, but factures of the breast bone are more prevalent in alternative systems.
Birds in non-cage systems have access to perches, but 50 percent of them may have a fractured keel bone or other deviation.
Ongoing research is looking at improved ramps and perches for chickens to avoid injuries. It is an instinctive behaviour, in which hens roost at night for protection against predators.
Smothering in open systems also occur when birds crowd together. It is unpredictable but seems to happen in the morning when birds cluster around nesting areas or feeders or crowd into corners. Separating the flock into smaller groups or blocking corners may help.
barbara.duckworth@producer.com
