JMO....
I like to start a bulldog out in a controlled atmosphere whether it be in a pen or with a hog tied up in the woods. I know how big the hog's body & teeth are. Its great to just take them hunting, but if that 1st hog you come to is a big bad toothy sucker & your new bulldog gets hurt or killed because he doesn't know what to do, you're right back to looking for a new bulldog when a little homework could have done a lot of good. I've had bulldogs that went from not knowing what a hog is to a solid catchdog with just a few hog experiences.
This is actually the best way of doing it but since it was a stray and you havent fed it for a yr etc. i just stated my .02 on how i would start a stray, it would perform fast or eat lead. I would do the above mentioned quote if I raised or really liked the dog. "even if you have gritty curs" :'(