Join Date: Jan 2012
Location: Calgary, AB, Canada
I have a horse that foundered, partly because I did not take his weight issues serious enough beforehand. He, too, was a very easy keeper and gained weight during the winter because the feeding was too rich in the boarding situation he was in. And I, too, thought that a little bit more weight during the winter wouldn't do any harm, especially in our harsh Canadian climate.
In hindsight, the management to keep his weight down would have been a LOT easier than managing the laminitis/metabolic issues afterwards. So I would be very, very careful.
Not sure what the climate is like where you live, but the sugar content in grass increases again during the fall, especially around and shortly after the first frost hits. Evening grass tends to be a little lower in sugar content than morning and daytime grass, so if you go ahead with this, I would get her used to increased periods of grazing in the evenings.
We have a closed snow cover here from pretty much end of October to end of April, so not much grazing in those months. So we just make sure the alfalfa content in the hay is not too high (10% or less) and make sure everyone eats only their own pile.
Not sure whether you have an arena available, but my horse does a lot better (both muscle and weight wise) with a steady workout during the winter, at least light work 3 x per week.