One of my hens slipped under a hole in our fence to cavort with the neighbor roo and got attacked by a dog for her trouble. I found the dog with the hen in it's mouth, hanging by her neck. The dog dropped her and bolted at the sight of me, and I managed to find the hen and bring her back to the flock (and plug the fence hole). I thought she was lucky and only lost a few months off her life, but now 2 days later I was petting her and noticed black, matted feathers under her vent. Checking to make sure no poo was encrusted on her I see a good 1"x1" hole on her backside, covered in yellowish slime. Turns out the dog got a chunk off her after all. I'm new to chickens and don't want to spend a fortune on wound care if it's as simple as how my momma treated our skinned knees -- wash it out, antiseptic spray, and neosporin the ever loving heck out of it. Am I right and need to raid my medicine cabinet, or do I need to see a vet ASAP?