well, currently Ted is eating like a trooper....a bag of Allen and Page Calm and Condition a week, probably a bag of chaff a month, half a bag of sugar beet probably and a bale of hay a day
Mine tend to get the same amount of hard feed in the winter as in the summer (their work load stays about the same) but I do add sugar beet to their winter feeds and cod liver oil.
On the other hand they get much more hay/haylage in the winter.
I couldn't eaven say per month.. have to buy feed every few months as I feed by the handful!! It the summer it's even less... Hay goes up in the winter - I'm currently going through 3 bales a week which I don't think is that bad for a 16 hh horse...