Patty is right. Don't mess with him during the day. If you know for sure he is still around, or even if you don't, put out some food and water out for him around his pen area. Try to locate where he is spending his nights and do what Patty suggests. Get yourself a net, like a fishing net, with a handle at least 3 or 4 feet long and with the net and light you shouldn't have any problem catching him. Hope you get him back before the varmits get him. Good Luck Amigo.
If he is hanging out somewhere, place a wire dog kennel cage with food in it within his sight, prefetably up against something on one side. Tie a long string to close the door from a good distance and wait..... i had one get out and was gone for three days. Found him walking with the chickens. Luckily i raised him and he came right up to me.
I would keep an eye out for him sometimes they return or somebody else may see him. Let your vets know and your Game Warden know because they may spot him while driving around since they go to remote areas.