Chester and bruster are commercial names for chickens with a high concentration of meat in the breast and thighs. Both are the result of a genetic improvement of chickens, obtained from successive crossings between selected females and males. It is good to make it clear that this technique is quite different from that used to obtain a transgenic product – which consists of the artificial manipulation of the genes of several species and not the selection of crosses. The chester, sold since the early 1980s, was developed from the crossing of different lineages of birds of the Gallus gallus species, of Scottish origin. 70% of the meat is concentrated in the thighs and breast, which also has a low fat content, a result of the diet of these birds, based on corn and soy.
The bruster comes from crossing birds of a lineage called Ross. “The genetic map of the bruster, like that of the chester, is kept confidential because otherwise anyone could produce these birds”, says veterinarian Luiz Alberto Conte, manager of one of the largest slaughterhouses in Brazil that sells such meat. Like the chester, the bruster receives exclusively plant food, without additives. The management of these two types of birds is also special. While a normal chicken is slaughtered after 44 days of life, weighing about 2.5 kilos, a bruster stays up to 60 days on the farm, reaching 3.6 kilos. The chester, on the other hand, lives for 62 days and reaches 4.3 kilos, on average.