American EnglishRearing Chicks and Pullets
Derived from the Latin for a young animal or bird pullus, a female chicken of less than one year old, or before it has started laying, is commonly known as a pullet. Rearing healthy pullets is essential for successful free-range egg production.
Basic Rearing Requirements
The basic requirements for free range systems are:
- Floor reared with access to perches and slats from an early age (e.g. from 10 days at the latest)
- Reaching target weight at key stages of rearing
- A vaccination and parasite health plan and programme implemented as advised by a vet
- Reared to an agreed lighting programme.
Birds should be reared under conditions that are similar to those they will encounter later in life. For example, both the drinker and feeding systems used during rearing should be as similar as is possible to those in adult life as this reduces stress as birds are moved from rearing to production conditions, which in turn reduces the risk of conditions such as feather pecking (Defra, 2001).
If pullets are purchased, the health status at delivery should always be checked before delivery as well as at delivery. Always check the chicks when they arrive from the hatchery or when you remove them from the hatcher. Chicks must be active, clean and dry with open, bright, and alert eyes. If chicks are looking dull or inactive a proactive diet including electrolytes must be considered.
What are the common causes of mortality?
Temperature and ventilation in the brood house are generally considered to be significant factors for mortality early in the chicks’ life. However, the quality of chicks introduced to the system is also an important consideration. If chicks arrive with a yolk sac infection, for example, then early mortality is likely to be high. But after one week of age mortality is more likely to be the result of predation, disease or smothering.
What level of mortality should be expected?
It is worth looking at mortality in the flock as two separate ‘time periods’:
- Mortality in the first week after placement
- Mortality from the second week onwards.
Mortality during the first week is often related to the quality of day old chicks, which is often outside the control of the farm. While a mortality rate of up to around 1.5% during this first week is not unusual, it is obviously worthwhile taking steps to minimize losses. The aim should be to keep mortality as low as possible throughout the life of the flock. If the mortality rate after the first week rises above 1% in any single day, it is important that the causes are assessed and addressed and further advice should be sought from a vet or poultry advisor. It is reasonable to expect a small number of chicks which are too small or weak at placement to die at up to seven days old. These are referred to as starve‐outs and it is important to ensure that these are not related to insufficient or poorly placed supplies of feed and water.
Bedding
Some form of bedding material or litter such as wood shavings, sawdust or straw is required that is absorbent and provides insulation from the ground. Litter from newspaper or cardboard or other material that causes the floor to become slippery should be avoided as a slippery floor can cause a condition called “spraddles”, whereby the hip-joint becomes dislocated and is frequently fatal (Hermes, 1996).
Maintaining Body Temperature
During the first few weeks chicks are unable to maintain their body temperature and so it is important that they are provided with conditions that prevent them from excessive heat loss or gain. The temperature and humidity in the brooding house should be kept at the right level. When chicks first arrive the brooding area should be pre‐heated to around 90F, with this temperature reduced by 5–10F per week as the birds grow and develop.Observing their behaviour at this time can provide an important indicator as to whether this is being achieved. Birds that are huddled together under the heat source means it may be too cold and this may result in smothering. If they are spread out, they may be too hot and if they all congregate in a particular area there may be a draft. If the birds are moving about easily in all areas of the rearing pen, then it is likely that the temperature is correct (Hermes, 1996). if it is too humid or too dry (aim for 65–70% humidity) then respiratory problems can occur.
If it is known that there will be temperature variations across the house, or if the temperature is expected to significantly flutuate, it is advisable to brood the chicks in a circular enclosure under a heat source so that they do not move to colder corners of the house, pile up and smother.
Controlling Campylobacter Contamination in Broilers
Campylobacter contamination of broiler birds can be a major cause of human gastroenteritis if meat is not cooked effectively. The identification of risk factors for colonization by Campylobacter during the rearing period is important in determining approaches to preventing contamination. In conventional broiler production, the main factors associated with an increased risk of colonization are the absence of hygiene barriers, the presence of other animals species, having a number of poultry-houses together and a warm season (Kapperud et al., 1993; Bouwknegt et al., 2004).
Under free-range conditions, it would be expected that colonisation would occur during the second and fourth weeks of life, when the birds are still indoors and in France, where there is significant outdoor production, more than 70% of free range flocks were found to be contaminated at the end of the indoor rearing period and before they have been outside (Huneau-Salaün et al., 2007). These results were obtained during periods of exceptional hot weather conditions, where the risk from birds, rodents and insects may have been increased as these are significant risk factors (Annan-Prah and Janc, 1988; Refrégier-Petton et al., 2001). Professional disinfection of rearing houses was an important factor in reducing transmission between batches. The number of inspections carried out per day can also be critical, particularly if poultry are not the main activity and insufficient time is allocated to this task. In the French study, inspecting the house two or less times per day was observed as a risk factor (Huneau-Salaün et al., 2007). Total freedom rearing, i.e. on an unlimited run, is associated with a higher risk of positive flocks from environmental contaimination. A system should be designed to limit the movement of soil and manures between indoor and outdoor areas.
Recommendation for the control of Campylobacter in free-range rearing systems:
- Disinfection of the poultry-house between two broiler flocks should be done by a trained hygiene specialist.
- An entry and exit gate to and from the poultry-house should be reserved for chicks only.
- Open-air runs should be enclosed with fences.
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