Your thoughts on stocking up?

I'm just wondering about the ins and outs of stocking up. I only really know the barest of details and today when Lacey was stocked up, I wished that I knew more.

It's been super snowy so Lacey has basically been just hiding in her shed, not really moving, for most of the day. She's basically acting like she's stalled...only she can leave but she doesn't want to and therefore refuses to leave unless I "force" her to leave. It is pretty funny though, when I go up there to feed and pick out her poop from her "stall" she does the whole 'stand really still, move very carefully, we're in close quarters' stall picking thing. Anyway, so both her back legs were a little stocked up this morning. They went straight back to normal after I made her leave the shed and lunged her at a walk, with a little trot, for about 10 minutes.

But anyway, what's "ok" stocking up and what's bad stocking up? Tell me what you know! :)
I assume that uneven stocking up or heat in the legs is probably bad...what about all 4 legs being stocked up but no heat and they're all even?

I feel like there should be a chart about this, like "call the vet if..." "encourage exercise if..."...

Thanks in advance! :)

I have a horse that stocks up on a regular basis all four feet and bad, but never any heat. He just doesn't like to move! He could be in the largest pasture and stand in one spot. But every day I would come to the barn, he would be stocked up, I walked him out or rode and he'd be fine again. But the next day it would be just as bad.

I've always been told it doesn't hurt them and just means a slower warm up. I would only be concerned honestly if it DIDN'T go away with exercise or if it had heat.

Funny enough, he is pigeon toed so I started him on a joint supplement to help out his pigeon toed leg. It was just straight MSM and ever since he's been on it regularly he is rarely if ever stocked up (in fact for a year I forgot about how bad he would get stocked up!) I didn't know if it was related or not, but a month ago I had to take him off the joint because BOTH tack stores were out and he started stocking up again right on schedule and just as bad as before. Never heard of joint medicine suggested for stocking up before that though.

I think it's primarily a circulation issue, or lack thereof. My TB used to stock up all the time after standing around for more than a few hours at a time. Hind legs more than fronts, but all would stock up to some degree. He'd be fine within 10 minutes of walking. Vet never seemed to think it was dangerous, but it always bothered me. Now that he's shoeless, and has more circulation going on in his legs, he never stocks up. Please nobody jump on me about shoes. It's just my observation of my horse.