Ivermectin is an antiparasitic so I can't imagine it working on fleas or ticks, but I'm really only familiar with it as used in horses via horse paste.
Of course, and it is effective. It doesn't, however, make billions for the pharmaceutical companies. The governments have promised they will get to throw out new drugs with high prices and patents. That is why its use isn't promoted by authorities. Same thing with hydroxychloroquine. Both have been around for ages.
Because they are sheep. Maybe Spunky is right to a point, but I think it has more to do with how it is processed and spun as a textile fabric. Wool army blankets are scratchy as heck, but a nice men's wool suit is soft enough to wrap a baby. It's how the fiber is spun and woven.