Quite simply, a wild animal's chances of survival are greatly increased when left in their natural environment. They are attached to her nipples but can be gently popped off with your thumb. If 7 or more inches long, have good balance and seem in good condition, are probably on their own so leave them alone. The mother will visit the nest within 12 hours. Mothers do not reclaim babies that are not in the nest.
Rabbits leave the nest and become self-sufficient at a very young age.
Rabbits rarely survive captivity, and if uninjured, should be released immediately. Young fawns easily imprint on humans which can be dangerous for both the deer and humans. Fawns must be reunited with the mother or raised in a rehabilitation center that can rear it correctly for release. The mothers will leave their young alone and feed elsewhere, so that predators will not be attracted to the helpless fawn. She will only come back to nurse twice during the day.