Broiler chickens are selectively bred and genetically altered to produce
bigger thighs and breasts, the parts in most demand. This breeding creates
birds so heavy that their bones cannot support their weight. As they are bred
to grow fast they reach market weight of three and a half pounds in seven
weeks. Broilers are raised in overcrowded broiler houses instead of cages to prevent
the occurrence of bruised flesh which would make their meat undesirable. Their
beaks and toes are severed without anesthesia, and the broiler houses are
usually kept darkened at all hours to prevent fighting among the birds.