Adding punctuation and cutting out the chat speak to make this easier to read....
Hi new here and too horse have an arab cross that someone left in my pasture. She is about 12 years old and was skin and bones she is putting on weight very slowly, but have noticed that now after her feedings she sweats bad. She is feed alfalfa pellets and equine (spelling) mixed it is making me nervous, and we have very little grass left as it is burning up here in alabama. Need to know if I need to worry bout her my other 2 horses are feed the same thing and are fine she does get free choice of hay but she is very picky eater and hay is crap around here and she does not eat it like the other 2 horses. I think she was stalled before because she does not look for forage like the other 2 horses, dunno anything bout her but have had her for about 5 months now and she is not putting on weight like I would of hoped. What are probotics keep reading about it bout not sure what it is vet has been out 3 times had her teeth floated has been wormed regular with ivamectin she had tape worm and was treaded for that as well will she ever gain weight? I always get darn hard keepers. FRUSTRATED and do not wanna give up.
I think you pretty much hit the nail on the head with whats wrong with her....the hay is cruddy and she's not eating it. Unfortunately, if you want to get her fat you're going to have to sacrifice money in order to get here there.
The cheapest option, IMO, is to load up on the alfalfa cubes and the pellets. Or try the timothy pellets. I have no idea what that other thing is, equine, since that means horse haha but if you get it at tractor supply, are you talking about the Purina Equine Senior feed?
You also didn't mention how much of everything she gets....thats important. How many scoops of each, and how many times per day?
As far as foraging, a horse knows how to forage whether in a stall or not. My Thoroughbred didn't even know what grass in a pasture was till he was 11, and he forages more in his stall than when he's turned out.