First let me say, your little guy is a doll baby! I'll take him. LOL! But, there may be something else going on that needs to be checked out. Has he had a thorough exam by a veterinarian familiar with horses? I've seen horses "stand under" themselves in the back (and their back "roached" up) if they have belly pain. The April photo of him, when he is standing "square" does not show a roached back at all. Does his manure look normal? Does he appear to be overly gassy? Something he is eating (sorry, some of the things you mentioned are not common on the equine menu over here) may not be agreeing well with him. Maybe he is slowly developing an enterolith which is slowly blocking his intestines and causing him distress. (I'm certainly not trying to frighten you, just make you aware that something other than him "turning into a dwarf" may be going on here.) I had a dog whose back started going out with slipping discs. He developed a roach back and started standing and walking funny before the discs got so bad that he could no longer stand. Even after his surgery, he walked roached back for quite some time until the pain subsided. He may have something going on with his spine. Again, I don't know anything about some of the food he is getting, but if it appears to be an "adequate diet", that is, other small yearlings are thriving on the same food and amount, then maybe he has some sort of "absorption" of the nutrients problem. I have a poor 2 year old goat that had coccydiosis before I got her and now as a 2 yr old, she is only about the size of a 6 month old goat, her ribs and spine stick out, her skin and hair coat are pitifully thin, and no matter how much or what I feed her, she just does not gain weight. Unfortunately, the only other goat I have, who is her stall mate, has a normal digestive tract and she is getting to be a tub of goo by getting her half of the meals. Does your little guy have healthy, pink colored gums? Compare his gum color to your other minis. If they look paler, he may be anemic and it may be due to an absorbtion problem. I don't know if horses can get coccydiosis, I've never heard of one getting it, but your little guy could have something similar. Sorry that this is so long. I'm just brain-storming and basically saying, while your guy is certainly little even for a miniature, and may have some dwarf characteristics, I wouldn't just chalk up everything you are seeing (skin condition, standing underhimself and roaching up his back) to being a dwarf. Good luck with your little guy. He sure is cute.