Eeek, poor baby! You should definetley take him to the vet. And since he can fit through your fence, well, first of all, how big is your yard? And I thought you had kennels for your dogs? Maybe, instead of leaving him out there for the pound to get, you should buy some kind of cable or chain and keep him in your backyard? If you can't get one, I would definetley be willing to send one of mine to you.