I think that’s different because there isn’t the obvious physical change, and because the female hierarchy is not nearly as intense as the male one. Castration in this case is not about preventing breeding, but reducing male behaviour. In Australia, North America and African sanctuaries, it is not recommend. Vasectomies are undertaken as they don’t impact hormones in the same way. I think female contraception needs to be considered within the dynamics of chimp groups too- having infants can improve a female’s social standing, and having oestrus swellings can make a female more popular with her male groupmates. The use of the pill doesn’t prevent these swellings, but implants usually do. In a case like MW, where all females are contracepted, I can’t see it making an impact aside from the lack of births.