Comment by autosharp

E.g. most chickens (about 2/3) that come out of their egg are male. But a flock only allows maybe 1 adult male for every 5 females, with the surplus murdered by other chickens. So almost all male chickens are superfluous in that sense. It is still selective pressure which makes chickens have 'too many' males, because apparently those chickens/flocks have created more of themselves.

Same for lions, btw, although I don't know about their sex' birthrates.