suggested we put her on half a scoop of sweet feed because she was a little ribby and we could feel her backbone. She has filled out nicely but is not too fat.
Hi, yeah, 'sweet feed' is a bit like Maccas for humans - junk food & so generally not the best idea. Cereal grain is high in starch & sugars, which is not great for horses, and difficult to digest, and 'sweet feed' is also dosed with extra molasses/sugar. **So saying, it's not *always* a bad move to feed grain, if there are no better alternatives. Important to feed it little & often, to minimise problems & maximise benefits. Grain & 'high octane' ingredients are best for horses in hard work, needing some extra 'oomph' rather than for putting weight on generally. For more weight, more hay is the order of the day to start with, and making sure she's not left to go hungry - if she's kept locked up at night, hay needs to be enough to last her till morning, for eg. It's not good for horses to go hungry for long & gut upsets caused by this can cause weightloss, among other things. Some alfalfa &/or beet pulp, ricebran, copra, and other high energy but low sugar, easy to digest ingreds are good in 'hard feeds'. Of course, ensuring teeth are in good order & she's not wormy, should also go without saying.
If you were only feeding half a scoop(how big the scoop/heavy? How many times daily?) that's probably a pretty small amount, and if the horse is healthy, no IR issues or such, just like a little 'junk food' for people, it would likely have done her little/no harm though, just provide a bit of a 'high octane' kick.
The managers at the barn are telling me to do myself a favour and take her off the grain because it is making her hot. They said that after they turned her out from a night in the barn she ran, jumped and kicked for over an hour.
Seriously?? She is a 5yo horse, acting like a HORSE, after being cooped up over night, and it sounds like under exercised lately!! As per above, yeah, she doesn't need the grain & IMHO best without it, but unless you're feeding her a fair few of those half scoops daily - or it's a huge scoop - it's unlikely a small amount will be the cause of her jumping out of her skin. Sounds like management is the issue. Especially if you can't exercise your horse enough, ensure she has 24/7 - or as close as can be managed - turnout with other horses, so she can BE a horse. And get more exercise too, which is important for her health & soundness, not just wellbeing.