Lighting in Poultry Flashcards
what are facts about chicken eyes
- large eye size
- highly developed sense of vision
- extended spectral sensitivity (including UV)
- excellent ability to see different colours
What are rods and cones
- photoreceptors found in retina
what is the difference between rods and cones
- rods are associated with night vision
- cones are associated with day vision
what is the correlation to brightness and chickens
- chickens are biologically designed for bright light
- chickens are more active during the day
- research has shown chickens prefer brighter light
- vision is a chickens major method of sensing its environment
how does light enter a chickens brain
2 pathways
1. through the skull into the pineal gland directly
2. eye- hypothalamus - pituitary gland - reproduction and body function
what type of light doesnt penetrate the skull
- low light intesity
- shorter wavelengths may not penetrate the skull as well (blue and yellow light)
what colour of light penetrates the brain better
longer wavelengths like orange to red
how is white light measured? is it effective
LUX
- based on human ability, effective for white light only
why is light intensity important
- manipulated to influence bird behaviour
- positive relationship between light intensity and bird activity
- common industry applications
what happens during low light intensity
- reduce canabolism
- reduced mortality (sudden death syndrome)
- reduce food wastage
- decrease bruising
- imporve feed efficiency
what happens in high light intensity
- eating and drinking
- mating activity
what factors need to be considered when choosing light intensity in broilers and turkeys
- chickens and turkeys prefer higher light intensity
- research suggest minor effects of light intensity on broiler production traits (growth, feed intake and mortality)
- low intensity increased yield of carcass, leg and wing portions in broilers
what factors should be considered in low light intensity for broilers and turkeys
- increases resting and reduces comfort behaviours
- increases breast blistering and foot pad lesions
- increase eye abnormalities and can cause blindness
- helps control canabolism and bullying in turkeys
what are fixed light conclusions
- early brooding - at least 20 LUX
- later brooder and rearing - no lower then 5 (low light intensity causes a negative welfare effect without any positive production)
- egg production - 5 LUX min
- natural and AI breeding flocks greater then 10
why should you use a dusk till dawn method
- its a gradual change in light intensity
- this allows birds to wake up in a timly matter and not all at once
- prevents crowding at food and water stations
- prevents agression and bruising on carcass
what is CLUX
- chicken version of lux
- based on avian visual capacity
- should be used for coloured lighting
what is the effect of wavelength on growth and muscle yield
- disagreement in literature
- green/blue light stimulate growth early on in life
- some research shows no benefits at all
what does green light stimulate
- stimulates satellite differentiation, leading to an increased breast muscle yeild (in the first three days after hatch)
what is the issue with research and experiements
- measured in LUX
how do emotional stressors have an impact on production
- adaptive states can lead to coping mechanisms
- chickens selected for low fear of humans had a higher body weight and laid larger eggs
- birds exposed to fearlful situations: reduction in growth and increased feather pecking
what are active behaviours in poultry
- walking
- running
- standing
- resting
what are nutritive behaviours in poultry
- feeding and drinking
what are comfort behaviours in poultry
- preening
- dust bathing
- leg and wing stretching
what are exploratory behaviours in poultry
foraging
what are abnormal behaviours of poultry
- feather pecking
- cannabolism
- stereotypies
what are some conclusions that can be made with blue light
- will reduce stress and a fear response
- plays a role in emotional states and welfare
in layers what colour length has a more stimulating effect
- red
- peak production is higher when using red light
what are disadvantaged when using red light in layers
- cant see blood or injuries as easily
what are important qualities to have in light sources
- quantity and quality (ability to distribute light to whole barn)
- initial cost (LEDs may be expensive initially BUT, they will save money over time)
- lifespand and durability (withstand the barn with minimal maintenance)
- operating cost (efficiency) - cheap to run
- opperating cost (efficieny - cheap to run)
- dimmable (reduce intensity for bird agression quickly)
what is photoperiodism and how is it implemented
- daylight control
- lengthening of days causes them to lay more eggs
what are the three rules of length and distribution
- extend daylight
- dont shorten
- do this at particular ages
how can you use photoperiods to control age
- An intermediate age at sexual maturity is desired
- timing is crucial - to early = smaller eggs, lower rate of lay, increased prolapse
- to late, there is fewer days to collect and you dont get enough eggs
- never increase length during brooding and rearing
what should lighting be during brooding and rearing
16L : 8D - light for chicks
8L : 16D - bring into lay
- the large jump is to sexually mature birds
how do you speed up sexual maturity in birds
- increase photoperiod beyond critical
- 12L-12D
- never decrease photoperiod length
what are the three rules of thumb with lighting
- never increase photoperiod length during brooding and rearing
- minimum of 12 hours of light is required for maximum stimulation ( easier in a commercial setting)
- never decrease photoperiod length during egg production
what is the difference between controlled VS natural lighting
- controlled : light traps fans and inlets (no external light)
- natural lighting : must take into account natural light patterns (try to follow rules as closely as possible)
what happens to broilers in dark light
- reduces early growth but body weight and skeletal development may be equal or superior at older ages
- can imporve feed efficiency : they eat alot more an hour before darkness, it sits in crop longer and breaksdown slower
- improves bird health ( prevents heart attacks because of better development and slow growing)
why does broiler develpment increase in darkness
- physiological changes in darkness (tissue regeneration)
- reduces early growth using extended darkness
- increased exercise
what are negatives of having broilers in darkness
- decreases carcass yield
- decrease proportion of breast meat
- however it does increase leg porportions
how does darkness imporve welfare
- growth - slower growing but better development
- mortality - better development or rest
- skeletal health and bird morbility
- increases activity and behaviour expression - play behaviour
will darkness make birds more difficult to handle at market
- makes them hard to catch
what happened during 23 hours of light
- less motivation
- less natural behaviours
- less feeding
what happened to eyes in continuous light
disrupts diurnal growth pattern, resulting in larger misshappened eyes - skull doesnt grow
- may lead to glaucoma - in turkeys it damages optic nerve and they go blind
what are positives of increasing darkness in broilers
- improves body weight at age of marketing
- imporves feed efficiency
- reduces mortality
- improves mobility
- wider behaviousral expression
- better diurnal rythms
- better eye health
what bird may not benefit from darkness
- cornish game hens, becasue it slows early weight and they are already small birds
what is the reccomeneded dark period
4 hours minimum but prefer 6-8
