I've been shooting a G20 in 10mm for a number of years. It kills pigs pretty well. Same manual of arms/trigger as my carry guns, accurate, inexpensive(the gun not the ammo!!), and pretty damned weather, sweat and blood resistant. The fact that it holds about 2 1/2 times as much ammo as the .44 I used to carry does is nice too(especially if you get into it with two legged prey). I carried the same gun as a hunting/woods gun up in MT for bears and didn't feel and more undergunned than I would with a .44. If you want to split hairs and get a little more power you could also get the Glock factory 6" barrel for it or an aftermarket equivalent but I've never felt the need.
If under 140# then you could get away with small caliber to the chest area. If over 140# then you'll need a large caliber to get through the chest area. Our do a shot right behind the ears on any size hog.