As the hen's requirement for energy is higher in cold weather than in hot weather, there are differences in the amount of feed hens will consume under these conditions. These variations in feed consumption are smaller for each degree change in temperature when the weather is cool than when is hot.
Between 7 and 14°C, each degree change alters feed consumption about 0.69%, while between 31 and 35°C each degree change alters consumption about 5.79%.
The optimum environmental temperature for layers for optimum feed conversions is approximately 30.5°C. The layers at this temperature require less feed for maintenance and could provide more nutrients for egg mass production.
As temperature drops, birds will eat more feed in an endeavour to maintain their body temperature. If the feed required to maintain body temperature and a high rate of egg production is greater than the quantity of feed consumed, the flock will reduce its production of eggs and egg size in order to maintain body temperature. It may appear blood and meat spots in the egg content.
A good manager must make an upward adjustment in the level of critical nutrients in order to meet the flock's daily requirements under such conditions.
While freezing conditions can be disastrous, the fiscal well-being and economic performance of the flock also diminishes when the house temperature drops below 13°C.
Observed Clinical Signs Happenings
- Egg production drops gradually
- As temperature drop, birds will eat more feed in an endeavour to maintain their body temperature. If the feed required to maintain body temperature and a high rate of egg production is greater than the quantity of feed consumed, the flock will reduce its production of eggs and egg size in order to maintain body temperature
Flock behaviour activity
- Decreased flock mobility or activity
- As the temperature drops the poultry houses may be unusually quiet because of decreased activity and reduction of normal vocalizations of the birds.
Feed Consumption Changes
- Feed intake increased as temperature drops, birds will eat more feed in an endeavour to maintain their body temperature
- Egg size reduce
Internal Egg defects
- Blood and or Meat spots
- Eggs from brown egg layers will usually show a higher incidence with a typical average of around 5.0 %.
- Brown-egg layers are very prone to produce a larger number of meat spots
Cold Environment (Temperature Below 24 Degree Celsius) in Laying Hens DOES NOT exhibit or manifest any of the following clinical signs happenings
- Egg production declines rapidly
- Mortality above the standard
- Visibly sick birds
- Decreased flock mobility or activity
- Droppings abnormalities
- Respiratory abnormalities
- Neurological Nervous
- Lameness or unusual movements, incoordination, ataxia
- Eyes abnormalities
- Head, Comb, Wattles, Face, Nostrils, Sinuses, Mount, Beak, Earlobes, abnormalities (except eyes)
- Body Parts (Neck, wings, breast, abdomen, shanks, legs, hocks, feet, joints, vent, and skin, abnormalities), skinny body, retarded growth, weight depression
- Feathers abnormalities
- Feed intake increased
- Diet or Feed Changes (Recent Feed delivery, Recent formulation /diet, Other silo or improper storage, another feed brand)
- Causing Agents
- Husbandry Environmental Practice
- Affected Systems/Organs
- Reproductive System
- Mainly Affects
- Egg Production, Egg Quality and Internal Egg quality
- Management and husbandry improvement. Although cold weather must be compensated for, warming the poultry house (shed) is much easier than cooling it. All heat in the building is supplied by birds, and the amount or air moving through the house must be reduced to conserve this heat. Insulation, draft-proof walls, curtains, and reduce fan speed all have their place in conserving heat.
- Suggested Actions
- Can be dealt with in house
- Technical assistance recommended
- Can be managed with feed additives, off-the-shelf medications
Impact on Egg quality
Impact on Liveability
Impact on Production
Overall Economic Impact
Y.M. Saif.2008.Disease of Poultry. 12th Edition.
Mark Pattison, Paul F. McMullin, Janet M. Bradbury. Dennis J. Alexander. 2008. Poultry Diseases. 6th Edition. page 29
Donald D. Bell, Williams D. Weaver. 2009. Commercial Chicken Meat and Egg Production. Fifth Edition. page 1053, 1213