I'm befriending a couple of crows

In a park near my university, there is a nest with two cows and a juvenile. I have fed them regularly since spring. They recognised me, and they didn't my my present near their nest. I would like to know if it's normal that I still can't feed them by hand? And I would also like to know if the juvenile crow i feed since birth will be easier to befriend.

Sorry for my bad english, it isn't my native language