The birds that are used to breed the chicks that become broiler meat chickens are called parent birds or broiler breeders. There are an estimated 75 million breeder birds in Europe.
Young broiler breeder birds are kept in relatively small single-sex flocks (about 2,500-3,000 birds) and are transferred to the production farms at the age of 16-21 weeks and stay there (in mixed sex groups). Egg production usually starts between 18-22 weeks of age and lasts until 60-65 weeks of age. Group size during the production period ranges from 3,000-8,000 birds and the percentage of males in the group ranges between 7 and 11 % when egg production starts.
The standard broiler breeder houses in Europe are mechanically ventilated and window-less, but in some countries it is a legal requirement that houses have windows (e.g. Sweden). Houses have a litter area and some proportion of the floor (normally not more than 50% of the total floor area) as a raised slatted area. Nests are positioned on the slats and can either be collective nests with an automated egg collection belt or individual nests. Maintaining a good and dry litter (often wood shavings or straw) is essential for keeping the nests and eggs clean. Enrichment is not commonly used in breeder housing, although sometimes perches and elevated platforms (required by legislation in Sweden and Norway) are present.
Cage housing of broiler breeders is rare, approximately 1-2 % of the parent stock in Europe is kept in cages. Some farms (mainly in The Netherlands and Germany), use multi-tier cage systems with groups of 60-100 birds per cage and with natural mating. A small number of farms (mainly in Southern Europe), have breeder hens housed in non-enriched conventional cages, single or group cages, with artificial insemination.
At the hatchery, besides being vaccinated, chicks may also undergo one or more mutilations, such as despurring, detoeing, toe clipping and beak trimming. These procedures have been introduced to reduce injury (such as feather and skin damage) to other birds in the flock due to (forced) matings or fighting between males. Beak trimming (using hot or cold blade or the infrared method) is carried out without any pain relief. De-toeing and de-spurring are also carried out without any pain relief (using a hot blade or hot wire).
Weight control is important during the laying period and separate feeding is applied for males and females, so that feeding is carefully controlled. Egg production and body condition determine the amount of feed provided. Food restriction is used to limit body weight gain and achieve desired levels of fertility. Feed restriction is practised because if broiler breeders were fed standard broiler diets, they would grow too rapidly and become too heavy to maintain good health before reaching the age of sexual maturity. This would have detrimental effects on their health, their fertility and their welfare. However, feed restriction causes welfare problems associated with hunger and increased aggression around feeding time.
In Europe, natural mating is mostly used. It is important that males and females are equally mature to prevent problems with sexually inactive males or forced copulations/over-mating and aggression towards females. This can lead to distress and injury in the females. Mating can be improved by using lower stocking densities, leading to more appropriate mating behaviour, such as a greater display of courtship behaviour, as well as fewer forced matings and less struggling of the hens39. The use of environmental enrichment can also be used to improve mating behaviour, reducing the frequency of forced matings.
Broiler breeders are usually reasonably well muscled at the end of their production period and weigh between 4 – 5 kg. As there is there is potential value in the meat from these birds, end-of-lay broiler breeders are sent for commercial slaughter, like standard broilers. There are rarely specific abattoirs for broiler breeders so breeders may have to be transported for long distances to reach suitable slaughter facilities.