Hmm... Do you know about deworming horses? The rotation schedule? Every horse needs to be dewormed about every two to three months. You don't deworm with the same type of wormer every time. For example, you could rotate from ivermectin to praziquantel, febendazole, strongid, moxidectin, and pyrantel pamoate... then repeat! Keep the broad spectrum dewormers rotating through, and don't use dewormers with the same active ingredient within immediate succession of each other. All horses, not just horses who turn up "wormy."
Deworm all of the horses that share a pasture with him – horses will continue to pass worms to each other, even when a horse is dewormed...
He's not being ridden, is he?
The hills were bathed in moonlight, the shadows not so stark;
Silver light reflected off his brown hide as he held me in the dark
– I love you, Mudpie!