Lecture 20: Species Specific Behaviour Chickens

Question 1

What is a laying hen?

Answer 1

-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

Question 2

What are hybrid layers?

Answer 2

-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

Question 3

How are broiler chickens different than layers?

Answer 3

-Very young and not fully feathered
-Rapid increase in body weight compared to previous generations, which affects locomotion

Question 4

TRUE OR FALSE: The most farmed fowl is chickens and the most farmed mammals are pigs

Answer 4

TRUE
-33 billion chickens in world

Question 5

What are jungle fowl?

Answer 5

-Ancestors of domestic chickens
-Behaviour of the modern hybrid is not that different from Red Junglefowl ancestor

Question 6

What is the morphology of chickens?

Answer 6

-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

Question 7

How is the digestive tract and bones unique in chickens?

Answer 7

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

Question 8

What are common behaviours for chickens and how does it relate to housing systems?

Answer 8

-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

Question 9

What are needs, priorities and preferences of chickens?

Answer 9

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

Question 10

What is foraging behaviour?

Answer 10

-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

Question 11

What do chickens and pigs share when it comes to foraging?

Answer 11

They both show contra-free loading
-Rather search and find food than be given

Question 12

TRUE OR FALSE: Chickens are more picky for the foraging substrate than dust bathing substrate.

Answer 12

FALSE
-More picky for substrate with dust bathing

Question 13

What is exploration and investigatory behaviour?

Answer 13

-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

Question 14

What is nesting behaviour?

Answer 14

Nesting behaviour includes:
-Nest site investigation & selection
-Pre-laying behaviour (gathering, sitting, building, floor scratching, crouching)
-Egg laying
-Post lay sitting

Question 15

TRUE OR FALSE: the highest ranked priority for hens is nesting behaviour over feeding

Answer 15

TRUE

Question 16

What is pre-laying behaviour?

Answer 16

-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

Question 17

What are some nesting behaviours associated with commercial production?

Answer 17

-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)

Question 18

How do chickens move?

Answer 18

-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

Question 19

Where is the centre of gravity in chickens?

Answer 19

2 places:
-belly for behind legs so extra equilibrium important for perchng
-In head like humans

Question 20

How do chickens perch and roost?

Answer 20

-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

Question 21

What makes chickens able to perch all night long?

Answer 21

-Digital tendon locking mechanism
-Less stress on muscles

Question 22

Do chickens have binocular or monocular sleep?

Answer 22

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

Question 23

What are comfort/ self-maintenance behaviour?

Answer 23

-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

Question 24

What is considered a bad behaviour related to preening?

Answer 24

Frequent, very short preening bouts: recovery from mild stressor or during frustration

Question 25

Why is space so important for behaviours?

Answer 25

-Hens prefer personal space but clump at resources such as feed
-475cm2 standing
-1876cm2 wing-flapping (makes impossible in most caged commercial housing)

Question 26

What is dust bathing?

Answer 26

-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

Question 27

What is Sham-dustbathing?

Answer 27

-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

Question 28

What is furnished/enriched cages?

Answer 28

-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

Question 29

What are non-cage systems?

Answer 29

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

Question 30

What is considered “free range”?

Answer 30

-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

Question 31

What are welfare potentials for ranging behaviour?

Answer 31

-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

Question 32

What are welfare risks for ranging behaviour?

Answer 32

-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