I have been around horse all my life. (1) tape worms are very bad for any animal and only cured with only a few dewormers . My question knowing from riding outside horses is how long has she been there . Long enough to worm?? Probably ...!! did she miss a worming
(2) was she fat when she got there? A change in diet and several hours riding will drop weight off a horse as quick as anything .. Just my opinion but would be askin lots of questions from here on out .. .. Apparently u trust this man or he wouldn't have your horse. And who's to say the horse isn't sick ( the one that is " skinny" ) . A thin young ( in shape) horse is way better than a fat horse standing in the pasture that knows nothing.
