priority welfare issues in laying hens
- housing
- feather pecking
- beak trimming
- bone health
behavioural restriction in laying hens
- is it important
- what behaviours are we worried about?
- Nesting
- Perching
- Dust bathing
- Foraging
> most contentious of welfare issues, driven the change in housing systems
importance of nesting to laying hens
- Every time a hen lays an egg, it is preceded by searching, nest building and sitting on the nest
- Most hens prefer to lay in a nest box
- hens will perform a variety of ‘costly; tasks to get the nest box
importance of perching for hens
- Hens perch in high places to avoid predators
- Hens prefer to rest on perches
- Hens may ‘work’ for access to perch
- It is well established that perching increases bone strength
importance of dustbathing to hens
- on litter hens dust bathe every 2-3 days
- hens sham dust bathe on wire floors
- after deprivation hens dustbathe more quickly and for a longer period of time suggesting internal build-up of motivation
- dont ‘work’ very hard for a dustbath
- pleasurable?
importance of foraging to a hen
- foraging behaviour dominates the time budget
- hens contrafreeload
- providing
- providing foraging substrate reduces the risk of feather pecking
Cages
* Conventional cages
* Furnished cages/Enriched colonies
> Small - up to ~15 hens
> Medium - 15-30 hens
> Large - 30 hens up to ~ 60
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Non-cage systems
- single-tiers non-cage banrs
- multitiered (aviaries)
- outdoor and free range
pros and cons of conventional cages for layers
- promote good health and hygiene
- but space and behaviour are greatly restricted
- and lack of exercise leads to weaker bones
furnished cages pros and cons
- include nest box, perches, litter area for scratching and dustbathing or more modern scratch mat
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Requirements – Floor space – Nest space – Perches
– Scratch mat
<><><><><> - Provide health benefits of the hygiene and
conventional cages - perches and more space increase bone strength
- furnishings support some of the behaviour patterns shown to be important to hens
non-cage systems requirements, pros and cons
Requirements – Floor space – Nest space – Perches
– Litter
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- Perch design also affects risk for injuries
- Litter in non-cage systems is mainly dried manure, which hens really like…
- But these areas become crowded - risk of piling
- Litter also leads to poor air quality and hygiene
non-cage and outdoor systems pros and cons
- Provide more space and opportunities to engage in a full range of behavior
- But increased risk of poor hygiene, disease and broken bones from flying accidents
- And problems such emaciation, feather
pecking and piling/smothering
<><><> - free range systems have highest mortality (second is free range aviary, then barn, then aviary…)
how have housing system mortlaities changed over time
conventional cages have been basically the same for a while, while furnished cages, multi-tier aviareis, and single tier aviaries have way less mortality these days than in previous years
Rearing Systems for Growing Pullets
- Hens housed in complex aviaries must be reared in complex environments
- Rearing in aviaries enhances spatial cognition, improves 3-D use of space and reduces fearfulness
- Rearing in aviaries affects bone and muscle development
Injurious Pecking in Laying Hens - types
- feather pecking: gentle (eploratory, stereotypes, or directed at particles) vs severe (removal of feathers)
- tissue pecking: mostly directed at toes or vent
- aggressive pecking: mostly directed at head and neck
Feather Pecking in laying hens
- what housing system? age?
- consequences?
- Occurs in all types of housing systems
- Large variation between and within flocks
- Increases with age – can start in the rearing flock
- Causes feather damage
- Consequences:
– Economic–reducedefficiency > More food or more heat
– Welfare – pain and discomfort
– Public perception
feather pecking cause
Feather Pecking is Multifactorial
* Hundreds of research studies
* Genetics
* Housing and management
– Rearing
– LayerHouse
* Redirected foraging but also…..
– Dysfunctional behaviour–like OCD in humans
– Fear, stress, brain neurotransmitters, gut microbiota…..
management factors that contribute to feather pecking
- Lack of foraging substrate (during rearing and as an adult)
- nutritional factors - type, method of feeding
> Food form, deficiencies, lack of fiber (feather eating) - environment
> group size and stocking density - stress from house climate (temp, humidity, dust, ammonia)
importance of FP prevention
- Once FP is established in a flock it is difficult to stop
- becomes a repetitive behaviour that increases in frequency and duration over time
- social transmission/birds see or learn from others
- is it a coping mechanism?
methods to reduce feather pecking and cannibalism
- Lighting
> reduce light intesity (but consequences)
> some prducers use red light > not clear if this is effective - environmental enrichment
> Foraging materials. Straw bales, pecking blocks
> shiny, colourful objects to peck at - beak treatment, beak trimming
> early technique was to trim the end of the beak by cautery blade but today most done by infrared beam which is less painful
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Management - Use of pullets without FP in rearing
- Low sound level
- Prevention of diseases
- Early placement before 20 weeks
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Housing - Provision of enrichment materials such as peck blocks, strings, baskets, hay bales
- Different levels (perches/aviaries)
- Provision of dry litter
- No flickering light
- Nests without lighting
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Feed and water - Use of mash instead of pellets
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In free range - High use of range- encouraging hens to go outside
where do we see highest levels of feather picking?
- Highest Feather Pecking in flocks lacking enrichment, with increasing age, in cage housing
- Highest Feather Damage in flocks lacking enrichment, increased age, absence of beak trimming, cage housing
- Confirmed the effectiveness of environmental enrichment in reducing FP and FD
The Beak as a Sensory Organ
- Birds use beaks for foraging, feeding, drinking, preening, nest building and as a weapon during aggression
- Serves as tool for pecking, grasping, moving objects but also is used as a specialized sensory organ for finding food, and for detecting chemical and thermal stimuli in the environment
- Within the dermis of the beak are numerous mechanoreceptors, nociceptors, trigeminal receptors as well as free nerve endings that also respond to chemical, thermal and painful stimuli
traditional beak trimming
- Hot blade trimming
> small hatcheries or on farm, hot blade cuts and cauterizes
> most invasive: can lead to acute and chronic pain when conducted on older birds
infra-red beak treatment
- most birds in canada - large hatheries
> Precision exposure of beak to infrared beam
> Beak tip sloughs in week to 10 days
beak treatment cons
Acute pain during healing
– Behavioural changes
– Reduces feeding, pecking
– Age and severity dependent – IR method at early age
causes less pain than hot blade
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Chronic pain throughout the life of the bird
– Can result in neuromas- tangles of nerves that grow during the healing process
– Spontaneous and abnormal discharge of neuromas can cause pain
– Age, severity and hot blade trimming
