What do you think...?

This is something we give our mare for breakfast and tea but may just start to give it her in the afternoons. We give her a handful of chaff, a carrot or two to cut up, also one apple cut up. Then we give her two frisky mare calmers and magic calmer(hyper horse) and some garlic flakes, around about a little sprinkle. I wanted to know if those is fattening, she is a welsh cob and I see other horses having breakfast and teas but not sure if the breed she is is suitable with this food? Any ideas? Best answer included. This will help a bunch!