What the crap is wrong with this horses ??

It should fill out as she gains weight. We had a horse like that for a while. If you want to keep her tail clean, put it in a tail bag. It's going to take a long time for the area to fill back in. So if flies aren't bad in your area and she can do without long hair on her tail, cut her tail hairs really short. It's not good to keep the tail wrapped for as long as she's going to be peeing and pooping weird. As for the holes, try stuffing cotton in there, although I have no idea how you're going to be able to secure them in there. If you do figure that part out, though, you'd have to change them out every day. You could even get a piece of plastic wrap and tape it to her, and let a flap hang over her , to protect it from any poop coming that direction and perhaps even redirect her pee. If you're going to tape things to her, I would clip her there first, although there isn't much hair in horses' nether-regions. Use surgical tape.