Considering "Alice" and "Betty" are friends there's probably no contract on the board is there? Where I board... if someone doesn't pay the board for a set amount of time it's considered horse abandonment and the owner of the stable takes ownership of the horse. That way has the right to sell the horse and isn't stuck paying for feed and care for the rest of it's life.

If there's any such contract I'd suggest Alice raise the board enough to cover the cost of all of her labor and expenses (and hell include enough to pay for a trim and a float while she's at it). When Betty throws a hissy fit and refuses to pay Alice (which sounds like something she'd do considering she shows the classic maturity level of a 11 year old) Alice would at least own the mare again.

I used to know a guy that floated teeth for $40 the old fashion way. He didn't even have to sedate my 17hh Warmblood (which the Vet always did). I paid $13.75 for a bale of pretty good alfalfa and $13.95 for my oat/barley. Shavings are now $7.85. That's why I only have one horse... cuz I live in CA and my conscience won't allow me to just say "I can't afford to get her teeth done... she's just going to have to deal"

Good luck with the situation between your friends!