Lecture 20: Species Specific Behaviour Chickens Flashcards
What is a laying hen?
-females which have reached laying maturity and are kept for the production of eggs which are intended to be for consumption instead of hatching
-Start laying 17-20woa
What are hybrid layers?
-Worldwide, 2 breeding companies provide almost all of the hens for commercial egg production
-Modern hens are the result of a cross b/w 4 grandparent lines
-Companies each provide a variety of genetic groups and within these groups there are several specific breeds; white layers; brown layers; etc
How are broiler chickens different than layers?
-Very young and not fully feathered
-Rapid increase in body weight compared to previous generations, which affects locomotion
TRUE OR FALSE: The most farmed fowl is chickens and the most farmed mammals are pigs
TRUE
-33 billion chickens in world
What are jungle fowl?
-Ancestors of domestic chickens
-Behaviour of the modern hybrid is not that different from Red Junglefowl ancestor
What is the morphology of chickens?
-Avian integument has diverse outgrowth (combs and wattles)
-Bare skin & epidermal outgrowths
-Skin produces & supports feathers & active in thermoregulation (adult bird)
-Largest feathers on tail and wings, usually diminish on legs
-Skin lacks sweat glands, contains blood vessels. free nerve endings, neuroreceptors, smooth muscles
-Integumentary glands: uropygial gland (secretions are deposited on feathers- anti bacterial properties) keep keratin flexible and feathers water proof
-Skin is thin and elastic for freedom of movement
-MOLTING: to reproduce feathers
-Ear lobe colour can indicate the colour of egg they lay
How is the digestive tract and bones unique in chickens?
Bones
-Bones of birds are lighter in weight than mammals some are hollow (pneumatic bones part of respiratory)
-Growth of structural bone types continues to grow up to the onset of sexual maturity (some medullary bones)
-Medullary bones is important for utilizing Ca for eggshell production
Digestive system
-Digestive tract is relatively shorter than mammals
-Metabolic rates are high to efficiently process food and keep body weight low
-Crop: storage
-Proventriculus: glandular portion of ‘stomach’
-Gizzard: ‘mechanical stomach’ grind food after soaked in gastric juices
-Ceca fermentation of undigested nutrients can recycle nitrogen important for urine and immune system vit B produced and fatty acids
What are common behaviours for chickens and how does it relate to housing systems?
-Foraging and feeding; exploring
-Nesting
-Perching, roosting, rest, sleep
-Locomotion
-Preening (maintain behaviour)
-Dust bathing
-Comfort behaviours
*matter bc some are affected/inhibited due to the housing system
What are needs, priorities and preferences of chickens?
Behavioural needs: Performed even in the absence of an optimal environment or resource (sham dust bathing on wire floor indicates that’s its a need as it is still performed in the absence of loose litter substrate)
Behavioural priorities: birds are prepared to work in order to preform or gain access to them
Behavioural preference: indicate the relative outcomes of choice experiments
What is foraging behaviour?
-Behaviour of animals when they are moving around in such a way that they are likely to encounter and acquire food
-Need 250mL and 80-100g of feed/day
-“contra free-loading” tendency to work for food rather than accept “free” food from a feeder
-Feeding behaviour can be divided into the appetitive phase (food searching: scratching pecking behaviour) and consummatory phase (actual consumption of food)
-50-90% of their time foraging
What do chickens and pigs share when it comes to foraging?
They both show contra-free loading
-Rather search and find food than be given
TRUE OR FALSE: Chickens are more picky for the foraging substrate than dust bathing substrate.
FALSE
-More picky for substrate with dust bathing
What is exploration and investigatory behaviour?
-Facilitates the acquisition of info about the environment
-Motivation to seek novelty for own sake (as long as not threatening)
-Motivation to seek a particular resource (target toward reward, foraging material)
-Chickens motivation to seek novelty- highly relevant to the topic of environmental enrichment
-Pecking in environment out of curiosity = intrinsic motivation to find something new
What is nesting behaviour?
Nesting behaviour includes:
-Nest site investigation & selection
-Pre-laying behaviour (gathering, sitting, building, floor scratching, crouching)
-Egg laying
-Post lay sitting
TRUE OR FALSE: the highest ranked priority for hens is nesting behaviour over feeding
TRUE
What is pre-laying behaviour?
-Always internal behaviour, 1 hour before laying get restless search for nesting material, indicates start if nest seek phase
-Hens prefer to lay in a discrete enclosed nest site with loose material
-Place high value on access to discrete, enclosed nest sites and their behavioural priority to access one increases the closer they get to laying time
-Prepared to pay high costs such as squeezing through gaps or opening doors to get access to nest boxes
-Hens delay egg laying when disturbed INDICATION OF IMPORTANCE
What are some nesting behaviours associated with commercial production?
-Commercial group nests are enclosed on three sides with front curtains and plastic grid or perches in front and the floor is usually covered wth astrotruf or rubber pimple matting
-Introductions of nest boxes into earlier production stages for pullets helps rain hens to use nest boxes and reduces the number of eggs laid on the floor (economic loss)
How do chickens move?
-Walking/running on the ground with their hindlimbs
-Jumping (up/down/across gaps) with or with out wings (jumping down harder than up)
-Wing assisted running with their forelimbs modified into wings
-Flapping-flight
Where is the centre of gravity in chickens?
2 places:
-belly for behind legs so extra equilibrium important for perchng
-In head like humans
How do chickens perch and roost?
-High percentage of night time roosting-highly motivated behaviour (protection)
-Motivation to achieve an elevated position vs motivation to grasp
-Height is the most important component (young broilers can’t use high perches so have to provide ramp bc 1. feathers not developed 2. very heavy)
-Chicks start to perch at 2w but start night time roosting at 6w
-Perches during rearing provide muscle tone development, spatial awareness and balance
-Perch design important for keel bone/foot pad integrity
What makes chickens able to perch all night long?
-Digital tendon locking mechanism
-Less stress on muscles
Do chickens have binocular or monocular sleep?
both
-Binocular when younger bc more safe
-Monocular when older have to be more vigilant (sleep with 1 hemisphere asleep while other is awake)
-Also helps to explain why birds can fly for 10 hours
What are comfort/ self-maintenance behaviour?
-Laying hens seldom preform activates such as wing flapping, stretching, body shaking, dust bathing and tail wagging
-Space so restricted that they can’t perform these behaviours so perform rebound behaviours which affects welfare
What is considered a bad behaviour related to preening?
Frequent, very short preening bouts: recovery from mild stressor or during frustration
Why is space so important for behaviours?
-Hens prefer personal space but clump at resources such as feed
-475cm2 standing
-1876cm2 wing-flapping (makes impossible in most caged commercial housing)
What is dust bathing?
-Involves the hen laying down and tossing, loose substrate onto her back wings, rubbing the substrate into her feathers and shaking out
-Combined with preening it improves feather condition by dispersing lipids and dislodging skin parasites
-Substrates like peat or sand are preferred over sawdust and straw, longer dust baths with all elements are performed in dust peat or sand
What is Sham-dustbathing?
-In absence of suitable litter substrate hens perform sham-dust bathing
-Not rewarding and do not satisfy hens motivation
-Similar amount of dust bathing in furnished cages and floor systems but most of dust-bathing in cages is sham dust bathing
What is furnished/enriched cages?
-Wire enclosed with extra space & elements: perches, beatbox (enclosed nest area), litter area, extra height (can run, flap, hump, dustbath etc)
-Variety of group sizes
What are non-cage systems?
Single level systems or multi-level systems (aviary)
Single level
-“Free run” inside doesn’t differentiate single or multi
-More space, perches, nests, large group sizes
Multi-level: Aviary
-Several levels of perforated floors with manure belts
-Feeders and drinkers are distributed in such a way they provide equal access for all hens
What is considered “free range”?
-access to indoor and outdoor area
-Covered verandas/winter grarden
-Concrete floor, usually covered with litter, climate is similar to that outside except for rain
-Pophes and nets
What are welfare potentials for ranging behaviour?
-High space allowance- general freedom of movement
-Environmental stimulation-full repertoire of locomotion. body maintenance (sunbathing, dust bathing) exploration
-Addition nutritive and non-nutritive food (plants, worms, little stones)
-High number of birds outside lower risk of FP
-Fresh air and UV-lightdisinfectionon
What are welfare risks for ranging behaviour?
-Destruction of the run, mud and intake for potential infectious agents
-Predation
-Selection of suitable hybrids
-Fences, dug into the ground=predation
-Trees, shelter, aerial predators
-Destruction of the run, weeks of regeneration
-Demanding in terms of labour
-Higher egg prices are necessary
