There is no mammary tissue involved, as in mammals. Because of this, birds never evolved to produce lactase, the enzyme necessary to help digest lactose. Essentially, birds are highly “lactose-intolerant” species. ... You may ask: How come my bird ate cheese and did not become sick?

Why can birds eat cheese but not milk?

Milk and coconut

Birds can digest fermented dairy products, such as cheese. ... A bird's gut is not designed to digest milk and it can give them serious stomach upsets or even kill them.

Are crows lactose intolerant?

Birds are all lactose intolerant (can't digest milk sugar), and if fed too much they will get diarrhea.)