>>63927074
>And how the fuck do infected give birth to non infected children and raise them
Implied reared by 'alphas' who are shown more developed and intelligent. It also appeared the zombies were washing themselves when they were splashing in the river, unless I missed something obvious.
I think they are going with the zombies becoming evolved or advancing.
The overall introduction of the dark haired hairy alphas is lending itself to the prehistory Britain currents in the movie, it also meshes with the folk nationalism the movie seems to appeal to