My Papaw always had a dog when I was young. The one I recall the best was the one that disappeared for a long period of time. I figured he had run off. Not many folks had fences back then. My Papaw told us kids, he drifted away. When he returned, he had lost a leg. Papaw didn't see a disabled dog that needed medical care, he saw his huntin' dog had returned.
The way my Papaw trained his dogs to tree squirrels was to tie one of the critters cut off tails to the dog's tail. I can't recall how long the dog had to wear that squirrel tail but it was longer than the dog was comfortable with and it would bite at it, tear at it and papaw might tie it back on day after day, but it stayed put until my Papaw saw some sign I wasn't privy to that let him know, the dog was ready to hunt.
It wasn't just squirrles either, that dog would corner or tree any animal after wearing a second tail for long that didn't smell right.
When Papaw thought there was a critter under his house, it didn't matter to him if it was a 'possum or a mouse, he would open the small crawl space door, shove Drifter under the house then shut the door behind him. At first it was quite a racket. The loudest was near the floor heater that took up most of the hall in my grandparent's tiny home. Drifter would slam into it with a clang barking like crazy. Then his barks and snarls would be heard under the floor in differnt rooms. I would try to track him from the safety above the wood floors, careful to step around the floor heater, even in the summer.
The longest time I remember Papaw leaving Drifter under the house was an entire day. Mamaw would not put up with the fuss at night. Most of the time, Drifter got out pretty quickly. That long time he was under there, he walked out with a tiny gray field mouse between his teeth. He pranced like he had been big game hunting and just bagged a lion.
Dogs like Drifter didn't want any reward. He seemed to know his job and he did it well. He did more with his three legs than most dogs could dream about in their twitchy dreams of chasing cars. Drifter's reward was being fed, petted by a proud owner and fenced in at night so he didn't have to live his life with any fewer than three legs.