In the case of hens, egg-laying hens are mutants compared with any wild birds. In the wild, no bird lays an egg a day, ever.
Cows can be mistreated and perhaps even most milk cows are mistreated, but giving milk (again in huge amounts with respect to the number of calves a cow normally would have) is not in and of itself, cruel.
It is not cruel to make shoes out of a deceased cow's hide, either.
It would not be cruel to make stuff out of deceased humans, for that matter: ghoulish, perhaps, but not cruel.