Im not really sure how long it takes for babies to be out of the nest and on their own. You may want to call a pet store that sells them. You have a lucky little mouse there, most folks would not be so kind. I know my baby chipmunks are out already. They are all so darned cute.

Unfortunately mice that had found a warm winter home in my compost pile were captured by my dog, when they decided to come out in the spring.

She is a lab and will stand, on point, in front of the compost bin, for hours, waiting for the mice to come out. Of course then she drops them, still alive on my feet, which is nice(NOT). Eventually she plays with them until they are limp. Its not something that I enjoy to watch, but I don't discourage her, because I don't want them in my house... which some of them do find a way.

I settled on a compromise. Turned out most of the compost. Left the bottom layer, with mouse tunnels, intact. Restacked it with plenty of twigs, then new stuff. Looks like the mice(mouse) is OK with that. I hope the hawk that visits appreciates this.