Is it the law for horses to have shelter available to them in Texas?

The horses at this barn don't have shelter available to them. In order to be out of the elements they have to be put in the barn by someone. Another issue is that the reason they are not in the barn when it is freezing is that the barn/facility owner shut the water supply off. Reason being is that the pipes for the 2nd year in a row have burst because they froze... The "owner" claims that the stock tank (pond) on the property is sufficient enough of a water supply during the freeze us Texans are experiencing right now. For one the pond froze over from the bank to about 8 ft inward... Another thing is that horses dehydrate easily in the winter because they don't often drink freezing cold water. There is a trough with a heater in it bought by the boarders not the owner, but the water keeps getting shut off so it can't always be filled. I want to know if there is a law somewhere that I can find that horses have to have shelter they can access themselves. AND if the whole water situation sounds unfair to anyone else, and not just me. (I realize many horses stand out in the rain, snow, etc. even if they have shelter available to them. It doesn't mean they don't need shelter)