Hens are highly motivated to lay their eggs in nests and exhibit signs of frustration when they can’t use a nest. Photo credit: CCSAW
The egg industry’s dilemma is to provide a “good quality life” for hens while producing a safe, clean and economically viable product, according to Dr. Tina Widowski, director at the Campbell Center for the Study of Animal Welfare, University of Guelph. Speaking at the International Egg Commission Conference in Washington, D.C., she said that it is a dilemma because many people have different definitions of what a good quality life is for a laying hen, and the industry must ultimately meet the expectations of people all around the world.
Widowski explained that one of the most stringent concepts of animal welfare, and the one held by most welfare activist groups, calls for animals to be raised in a manner where they lead a relatively natural life and behave in ways that are consistent with the nature of the species. Hens don’t have to perform all behaviors to be considered to have a good quality of life, according to Widowski, but some may be particularly important.
Four important behaviors
Research studies have identified nesting, perching, foraging and dust-bathing behaviors as having welfare impacts on laying hens. Experiments have been conducted to test the motivation of hens to engage in these behaviors in a number of scenarios.
Laying hens are highly motivated to lay eggs in a nest box. When given the chance, over 95% of hens will lay their eggs in a nest, Widowski reported. Nesting behavior is caused by hormones released during ovulation. Hens like to lay their eggs in an enclosed space and will do work or walk by a dominant hen to get to a nest box. Widowski said that hens like to lay eggs in a nest box and show signs of frustration if they don’t have a nest box. Nests in enriched cages are curtain sided and have some kind of different flooring material besides the wire of the cage.
Chickens are descended from jungle fowl, and like all galliforms, are ground-foraging, communal birds that roost above ground at night. In nature, hens perch to avoid predators, and perching behavior seems to calm birds down, even birds in cages. Leg bone strength of hens is increased by perching. Hens prefer to rest on perches and will sit on perches at night, but research has shown that hens will do little work to get to a perch.
Foraging is the pecking and scratching naturally associated with searching for food and feeding behavior in hens. Wild jungle fowl spend 61% of their time foraging for food. The strains of hens selected for egg laying are generally not willing to search for food and are generally not willing to work for a substrate to scratch, but hens do exhibit some aspects of this behavior as they move back and forth at the feeder, according to Widowski. Foraging behavior may still play an important role in hen welfare since some researchers suspect that feather-pecking behavior is a form of redirected foraging behavior.
Hens with access to litter will dust bathe every two or three days. The behavior is believed to have evolved to remove parasites and maintain feather condition. Hens will sham dust bathe on wire floors and will dust bathe more quickly and for a longer period of time after going without litter. Hens do have preferences for different substrates: they prefer peat moss, but hens may or may not work for access to dust bathe. Widowski said that hens tend to work harder after deprivation of dust bathing, but not that hard. Hens exhibit few signs of frustration when denied access to dust bathing.
Scratch areas in enriched cages are designed so that hens can forage and dust bathe there. Commonly, a material like a mat or artificial turf will have a little feed augured over to provide material for foraging and dust bathing. There can be some hygiene problems with scratch areas. Some enriched colony systems are now using smooth mats because they are easier to keep clean.
Group size and space
Low perches like these can have a calming effect on hens and they help to reduce the number of broken eggs. Photo credit: CCSAW
Laying hens are communal animals, and when placed in a colony enclosure they tend to group together. If enclosures all have 1X space per bird, then the enclosure with 50 hens will have more unoccupied or “free space” than an enclosure with 10 hens. Widowski said that this is why colony enclosures have gotten bigger. She said that up to around 50 hens per colony is good, above this level the free space per bird will still increase, but not by much. Free space is important for wing flapping, which requires the most space of the normal behaviors.
Widowski evaluated the welfare aspects of the three major hen housing systems: traditional cages, cage-free and enriched colonies.
Traditional cage systems have restricted space, don’t allow for all behaviors to be performed, hens have weak bones because of lack of exercise, and feather pecking and cannibalism can be a problem. However, they don’t have as many broken bones as cage-free, hygiene is better and disease is limited in these systems.
Cage-free housing does not have behavior or space restrictions, but broken bones (Widowski cited keel and wishbones breakage problems in UK cage-free systems), feather pecking, cannibalism, hygiene and disease can be problems.
Furnished colonies don’t have problems with space or behavior restriction; have hygiene and health advantages over pens and free range; perches improve bone strength over cages; and feather pecking and cannibalism are improved as well.
“Enriched colonies seem to have fewer problems for welfare than do traditional cages or cage-free,” Widowski said.
There are three challenges for the future for enriched colony enclosures, according to Widowski:
Key issues for welfare of hens in different types of housing:
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Mats, like this smooth one, encourage hens to engage in foraging and scratching behaviors as well as dust bathing. Photo credit: CCSAW
Dr. Tina Widowski said, “Enriched colonies seem to have fewer problems for welfare than do traditional cages or cage-free.”
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