Of course being out 24/7 is ideal but most horses do just fine if they need to stay in during inclement weather. I personally like to blanket and kick them out (they have a huge run in) but i stall when need be. Some horses are stalled pretty much all day...
Charlie Brown (1994 bay TB X gelding)
White Star (2004 grey TB gelding)
Windward Farm, Washougal, WA- our work in progress, our money pit, our home!
I stall my horses at night (I have 2 at home) from roughly late September to April. I have a 12 foot overhang attached to my barn, with Dutch doors that open to it, and a sacrifice paddock beyond that, with pasture a gate away. They haven't had any issues with being confined, out of the wind and rain (never ending, cold, nasty, spitting rain). We have very strong winds where I am located, and the boys get cold, even in blankets. They seem quite happy indoors, with no ill health effects from stalling. I know my elderly boy gets all his food, and a chance to lie down in dry bedding.
Proud member of the "Don't rush to kill wildlife" clique!
I've done this for almost 40 years. My pasture is small. Only four acres. So my horses get fed before going out in the A.M. and come in for P.M. feeding and stay in all night. This keeps my pasture from being overgrazed and the horses still get plenty of free time to just do horsie things.
Any time you stall a horse "long term", whether that's all night or all day on a regular basis, or especially all the time, you DO increase, however slightly, the risk of colic. Horses' guts are designed to work the best when the horse is nearly constantly moving.
Suddenly stalling a horse who is used to being out, even if it's just 1 night due to nasty weather or whatever, can increase the risk if he's a worrier and doesn't like change or just has a real aversion to being stalled.
That said, thousands and thousands of horses are stalled "long term" and never colic. Many many horses are on that 12/12 schedule, in stalls at night during the Winter and in during the day in Sumer, or just in at night, period.
Is it healthier for them to be out all the time? For the most part, yes, but it can be unhealthy for a given individual horse depending on his particular issues.
______________________________ The CoTH CYA - please consult w/your veterinarian under any and all circumstances. - ET