So I've done this before and I'll keep doing it. You tend to get hundreds of horses while breeding for that magical one. I hate disposing of them so I have hundreds of chests full. Every once in a while I clear out a chest to make room for more. lol Some times I go into the /wild and release them other times I go to the /waste but I't so rewarding to know their code will live on and perhaps one day some one will find them and bring them back to town.
I've ended up with countless DC's of horses, and I normally just stick them in a pit and kill them. Sorry. :/