Depends on a lot of factors. 1) what kind of fencing do you have v. what kind he was used to - if you have electric, and he's used to post & board, I'd say no. Other way around, fine. IF he's used to the same kind of fencing you have, I would take him on a lead, and walk him around the perimeter, and I would let him loose once he settled down - most will relax pretty quickly. For a youngster, I'd take a few days and see how he is, and just make friendly with him. If he were trained, I'd say let him settle, then work him asap.
Ask Often, Demand Nothing, and Reward Generously.