What is the minimum open-enclosure requirements to keep a horse all night? Is a stall any different?

Many horses are kept in 12 x 12 stalls. Some are even kept in 10 x 10 stalls, which is too small, IMO. Horses do best on pasture, though. When I was a kid, I boarded my horse at a place where a strange girl kept her black Morgan in a chain link DOG KENNEL. No shade. I thought it was cruel. Apparently, she didn't want him mingling with the other horses.

If the horse has food and water, nothing can be done. Certainly less than ideal, though.

While most of us will agree that chain link fence isn't a good choice for horses, it may be a somewhat suitable condition for the animal. Most prefer to be outside as much as possible, and if he's getting ridden during the day and then standing in a little yard at night he should be fine. Many horses are stalled 90% of their time in a barn, that life is less healthy than being outside at least overnight.

That horse has it better than many, who are kept stalled day and night, often without turnout at all. Ideally every horse would have 24/7 turnout with large pastures and companions, but that's rarely possible.

Horses can be happy and healthy in the situation you describe. It's not unethical.

As long as the horse is in good flesh it's fine.

It's nice to wonder. It's delightful to keep your nose out of other peoples business.

If that horse is seen from the road... everybody from a bunch of "qualified horse owners" police officers animal control and welfare people drive by it too.

When I was a kid... my uncle lived on about 5 acres right on the edge of town. Their horses lived in a modified garden shed... and grazed the yard with a long line tied to a concrete block every day. Not exactly Churchill Downs back row. Those kids could ride like wild indians ... and those horses brought home a ton of 4 H ribbons. They got hauled in a stock rack on a pick up truck.

I still get crap from doo gooders for hauling my working horses to pasture whist saddled in the stock trailer.

Pick your battles and don't get caught on the low ground

There are two separate issues here. One is the welfare of the horse. The second is whether the situation of the horse is of concern to anyone other than the owner.

Many horsemen (myself included) look askance at people who express concern for horses. They have heard barbed words and seen meddlesome behaviour, apparently directed at "doing something" with or about their horses.

Horse ownership is rather specialised. Just as caring for a dog is a bit more difficult than caring for a cat (cats being rather self-sufficient and aloof), caring for horses requires thinking that is not understood by the casual non-horseman. If, for example, you see a horse, alone, tied to a wall, is that abuse? How would you know? Similarly, if you see a horse that is a "rack of bones" is the horse being starved? How would you know?

Horsemen might recognise (1) a training session and (2) the rescue or the difficult care of an elderly horse on death's door. When we have a horse that is doing poorly, where we and the vet are trying to understand failure to thrive, we keep the horse in a back pasture, unlikely to be seen by those who would want to report "abuse." We worry that public view of an ill horse would result in legal (but immoral) confiscation of all our horses. Our community used to have a "concerned citizen" person who would get herds condemned, be allowed to take them all, and sell them to the meat market--a horse thief.

If you see a horse in what appears to be a bad situation, you might first wonder if the owners themselves are also in difficulty. Perhaps a horse that's not been fed belongs to a lady who lives alone and who is lying on the floor with a broken hip, hoping someone will knock on the door to see if she's all right.

The older I get the more I worry about that sort of situation. But I don't want to be bothered by meddlesome people who might be horse thieves.

In times past. horses were regularly housed in tie stalls no larger than a decent horse trailer stall. They were used or turned out during the day.

Try not to be a busybody.

Remember too that what you consider "teeny" may be the normal for those of us that have horses. If the horse can turn around easily, lay down comfortably, etc, then it is not too small. 12 x 12 is very common. If you care about horses, find a horse owner and offer to pay them for a "lesson" about horses. Most owners are open to teaching folks, and offer of money will probably be appreciated because you are taking time. However, I much rather have someone ask me why we do something with our horses, or if laying down means they are sick (it does not. Mine lay down every morning after breakfast) than worry about my horses

They have a decent maintained house, single horse transporting trailers, etc....maybe I am overreacting. I am just making sure the horse is OK though. I like to keep an eye out for these things. I will keep this updated.