Ahh, okay, gotcha. Lol I was sitting here wishing I could just give Tara a treat twice a day and she'd be fine =P
Well during the winter, the grass mostly dies, but there's usually a teeny bit left. It looks pretty sad, but I'm sure Tara would pick at it if there was nothing else. Or she'd crib. Actually...yeah, she'd probably just crib!
Okay, just read a story about a horse that moved to a barn that did separate hay feedings instead of free-choice, and the horses would go most of the night without hay (after they finished their evening feeding), so one coliced. I'm terrified of colic...what will she do in the winter when she finishes her 2 flakes?!
The big question is how big are the bales/flakes? A flake out of a 35-40 lb bale would weigh different than a 60 or 80 lb bale. Once you have that information it will be much easier to determine if that is the proper amount. 6 flakes out of a 35-40 lb bale would be fine for a easy keeper. That is what my haflingers get in the winter, but I doubt that would be enough for a hard keeper. On the other hand, 6 flakes out of a 60 lb bale would be way too much for an easy keeper but adequate for a hard keeper.
You could also supplement with a "complete feed" that has enough fiber in there to count as a forage or beet pulp during the winter.