Do you guys get the super cheap grass hay up there, like we do here? The stuff that's just someone's random field, baled?
What I do is I stock up on those bales and just feed as much of it as Lacey wants. I make sure she always has enough to really chow down, if the mood hits her (I keep it somewhat collected in a stall corner/hay rack so it doesn't get soiled+unedible).
Then, I supplement with about 5lbs of alfalfa/day and a ration balancer, with a pound of beet pulp mixed in if Lacey appears to be loosing a bit of weight (that usually happens during the coldest bit of winter).
I find that the grass hay is cheap enough that even going through 1.5 60lb bales a week (during the coldest part of the winter, usually it's a bale-3/4 bale/week) and about half a 120lb bale of alfalfa, I very very rarely exceed my goal of not spending more than $10 on feed/week (barring weeks where I have to buy a new bag of ration balancer).
And Lacey stays a healthy weight. Not obese like she is pretty much all summer (thank goodness) but a healthy, ribs have a thin layer of fat but can't be seen through her coat, energetic weight.
In Lacey's case, the alfalfa is the real ticket. Without the alfalfa, she'll lose tremendous amounts of weight no matter how much grass hay she's eating. I figure that the grass hay just doesn't have enough protein in it for her system to function properly.
I couldn't handle, $$-wise, just feeding alfalfa (not sure how good that would be for her anyway, haha) but so far, 2 winters on this system, the results (of what? The clinical trials I've been running?
) have been exellent.