I would consider it weird, unless there had been something going on with one of the animals in that stall. If one of them had got cast, or was banging around a lot all of a sudden or something like that, I would think it too weird, they were just helping the horse before he/she got hurt. But if nothing weird was going on in that stall, and they all looked normal, ect., then I would wonder why exactly they were in there, when the entire point of their visit it to treat the horse that actually has the problem. Did your mom ask them what they were doing? That's the first thing I would have done, is ask hey, what are you doing, was something wrong with the horse or however it would be worded, nicely of course, and then get on with the matter of actually helping with the horse they were supposed to be treating.