Just recently I’ve been reading up on if dairy products can be fed to your birds or not. Well according to this very informative website it shouldn’t be fed because the avian digestive tract can’t digest lactose. It states that it can cause severe allergic reactions, obstructive disease and even death.
Even though this is most likely true, I’ve read that it is common among budgie breeders in the UK to feed their young birds bread & milk. I’d rather just not take the chance with feeding my budgies any dairy products because they can get all they need from other healthier foods. They may or may not be lactose intolerant, but I’m not going to be the one to try and find out.
My opinion is to avoid it if you have any doubts of its safety.