I don't actually think it's that simple to 'repo' and sell a boarder's horse - I think the barn owner has to go through some bureaucracy and that there would be a paper trail, but as I don't recall the details, I'll look it up.
But I do know one thing - that in the US, the laws on that are at the state and local level. So it depends on your state and local laws, whether a barn owner is allowed to do that or not, and exactly how he does it. So it depends on where you are.
In general, barn owner/managers don't do this until the situation has become really desperate - the horse owner has disappeared and abandoned the animal for months, or simply refuses to pay.
Nor would I simply assume the barn owner was 'mean'. We always have to remember that the horse business runs on one main fuel - gossip, and what you hear about a barn owner may not necessarily be true - at all.
This is just one of the many things, though, that makes it all the more important to have a written boarding contract that both owner and barn manager/owner sign - and stick to. The typical arrangement, 'we do this this and this', 'okay, I'll move my horse here', it just really doesn't work out very well when a problem pops up.
And also, just another one of those things that point out that no one should get a horse if they aren't absolutely sure they can keep on paying board, on time, very consistently.
The right to sell a horse for unpaid board is usually called a 'stablekeeper's lein', and at least in Texas, it doesn't include tack and equipment - only the horse. It's found under the Texas Property Code law. And in Texas, the horse cannot be sold privately - it must be sold at public auction. The barn owner must make written request of payment and the non payment has to go on for several months.
Most likely, there would be some notice of the public auction.
This site has a list of all state laws, but I don't know how up to date it is -
Actually, the boarding facility cannot legally sell the horse or its tack without going through the legal motions of filing paperwork and getting a court order. Otherwise they are selling something for which they do not have legal title and can be sued. I know owners do just sell the animal, but they leave themselves open to possible law suits when they do that. The original owner CAN charge them with theft. I've seen it happen.
I think you might be confusing civil and criminal cases (lawsuits for a financial wrong vs criminal charges of theft), and all states are very different in exactly what they require to have this done, in the way of procedure, notice to horse owner, time interval, whether that includes tack or not, etc.
I do believe, depending on the state, if a barn owner sold a horse when he did not have the legal right to, that he could be sued as well as charged with a criminal offense. But the two things go very very separately and differently.
Nearly all states do have SOME sort of stablekeeper's lein law. But how it goes - very different in each state.
This is really the trouble with laws that states make - while they have similarities, they just really are not the same. What happens really depends on where you are.
In fact, in nearly all states, almost any animal care taker (and animal usually means anything other than a human) has SOME type of 'agister's posession', which legally means he has a type of posession of the animal - because he takes care of it or provides a service to it.
And in many states, service providers, such as stallion breeders, farriers, even veterinarians, have some rights to a level of posession on an animal for unpaid services.
Just one more reason why not to take on an animal unless one has very consistent funds to support it and pay for all services very promptly - and get a signed, detailed boarding contract.
I used to work at a small ranch that also boarded a few horses on the side.
One of the boarders was chronically 3 months behind on her board. EX. Brought horse in Jan, paid to feb and didn't pay again (for only one month) until April. She scheduled vet and farrier appts for her horse but never showed up herself. Stranegly evenough when vet or farrier billed her, she paid them. Into next winter she became 6 months behond onboard which at that time it was appropriate for the stable owners to seek legal recourse. Lengthy, firm attorney-penned letter was sent to her and within a few weeks she moved her horse. They never saw another penny of the board they were owed. Shortly after that, they gave other boarders 30 days notice to find new stables. My husband and I remained, mainly because we were also part time employees and they could dock our pay. That was uncessary of course since we paid diligently anyway.
Usually, the stable owner has to wait a specified period of time before filing a lien.
It varies from state to state, as wc says -- you will have to research the laws in *your particular* state. In some, there has to be some sort of legal thingie filed; in others, as long as certain requirements are met (length of time, advertising, notification, public auction) I do not believe any governmental paperwork would exist.
Usually when a person goes to a boarding stable there is a contract and in that contract there is the legal language about liens, medical billing/fatal issue with a horse such as severe colic, emergency contact numbers (so the barn owner can reach the owner of the horse), late fees and other legal type items.
IF the boarding stable doesn't have that, or the horse owner never signed one... then the barn owner/manager has to file a lien against back board owed.
Legally at that point the horse owner cannot remove the horse, sell the horse (unless the owner and the BO or BM come to an agreement that the horse is sold and the amount owed on the board is paid).
Once a liens is done and the horse owner does nothing, the BO/BM can sell the horse a sherriff's auction can be done, or they can sell the horse for back board.
Usually if the amount the horse is sold for is more than the amount owed, the extra money has to go to the former owner.
Registration papers can be lost that way. And sometimes the lien must be posted in local papers.