Join Date: Mar 2011
Location: northeast Arkansas
Well I'm not here to judge anybody, it's not my place.
If the OP is still around, post pics of the horse so we can get a better idea of how he looks. If his spine is sticking up like you say, then he's probably pretty thin.
I know first hand how hard it can be to get a vet out when you're young and your parents pay for most of your stuff and you don't have your own money.
First, I would definitely always feed him seperate, and I think a good idea would be to put him in his own pen where he can get all the hay he wants and finish his grain without being bullied.
You said he was up to date on deworming, but if you use the same drug class of wormer every time, those worms build up a resistance to it. What brand did you use last time, and what did you use the time before that? If you haven't already, go ahead and use a wormer that includes tapeworms. Most don't, but I believe there are 2, maybe 3 that do.
What kind of grain does he get?
Does he act like his teeth hurt?
-Does he spit out wads of partially chewed food?
-Does he tilt his head when eating?
-Under saddle did he shake/toss his head?
Does he seem lame?
In bad weather does he have shelter? Cold horses actually lose weight when they shiver and if it was a particularly long stretch of cold weather, plus add in the fact that he gets pushed away from feed, then that could explain why he's lost weight recently.
Have you noticed any diarrhea?
Does he seem less energetic when you ride, or is it the same no matter what he's doing?
It could be something very serious, or it could be a heavy worm load. I would start by seperating him, and deworm him with the tapeworm dewormer if you haven't done that. If he's still being rode, I'd switch it up and take him down the road or do something different. Horses get bored just like we do and when they get bored with their work they tend to get lazy and shut down. If he's real thin I'd just give him time off.
Keep an eye out for lameness, diarrhea, teeth problems,etc.
You can add wheat germ oil, corn oil, or another fat supplement to his grain, and alfalfa hay is really good for adding weight. It is higher in protein than just grass hay.