I wouldn't think it's too much. Is your pasture good? I am sure they get more than enough forage from the pasture, but it makes them feel better to have a flake or two,lol. Yes, you could cut out the hay and they would probably be just fine, but I wouldn't say, in my opinion, that you're over feeding hay.

A lot of people don't feed grain unless they have to. If the horse doesn't keep weight on, is old, young, etc... However, I do give grain every day. If I'm not riding much it's MUCH less than it would be if I was riding every day though. Jackson would miss his pellets,lol. I use a probiotic as well, and this increases the efficiency of their digestive system so that he is absorbing everything he needs from what he eats. This cuts down on his grain even more, he's a VERY easy keeper,lol. I don't know what your finances are like, but I really like the results I've gotten from the probiotic. Skin, coat, hooves, he's in excellent condition since I've started giving it.