I come from a family of cattle breeders. I breed top quality show Labradors. When we breed cattle or dogs, we consult pedigrees about to four generations because many traits skip generation and remain hidden.. However, in Cockatiels I have noticed that for working out mutations breeders only look in the colour mutation of parents. Even the genetic calculators talk about the colour of parents. I want to be educated why breeders feel that it is only the parents which matter.