Need help for weight loss.

I haven't really been able to ride my horse since last summer, but even before then she has gained quite a bit of weight since last winter. The farrier has told us that she had early signs of lamintis showing, so we cut back her hay. She's lost a bit of weight, enough to be noticable, but not enough for her to be considered a "healthy weight". I haven't been able to work with her during last summer as much as I really wanted to, due to breaking my right foot twice. I hadn't been able to work with her over the winter either, due to the large amounts of snow and ice. We don't have an indoor arena or anything, we just have a small barn with enough room for three stalls, hay, and our tractor. We also have a paddock and two pastures. During the winter we keep the horses in the dirt paddock, so they don't tear up the pastures. Now that it is getting warmer out, I'm beginning to work with her again and my foot is getting better, although I still have problems with my foot and my hip from previous accidents.

Anyway, getting to the point... Could you guys help me come up with a good exercise and diet plan for her? She's a 16 year old mare, about 14.3hhs. She's a crossbreed of Friesian/Arabian/Welsh Cob.

Since I'm in class right now, I can't put any pictures up of back when she was a healthy weight, to what she looks like now. I will do that when I get home. Any help would be greatly appreciated.

Since she's over weight she doesn't need a lot of calories. You could stick her on just hay but unless you have super great hay she may not be getting all the nutrition she needs. I would put her on a Ration Balancer or vitamin/mineral supplement(Same things really...) so she gets the vitamins and minerals she needs but doesn't need 5 or 6 pounds of grain to do it. Can you lunge her any or on the days when you can't ride?

I let her and the other two geldings out in the morning, and we spread out two bales of hay for them. Then when I bring them in at night, I give her two flakes of hay. I don't usually give her grain, unless I've given her a good work out. And yes, I can lunge her. The only thing is it gets so incredibly muddy here, so it's hard to do anything.