Hell, even the horse apples in the yard dont stand a chance now a days.
After about a day, the apples are nothing but cellulose.
I worm my horses about every 4 months, and use the Ivermectin paste. It takes forever for their chit to go away, and I'm guessing it's because of the lack of dung beetles. I'd hate not to worm the horses, and I could take them to the vet and have it done, but it's so much cheaper to do it myself.
At one time, I let chickens run in the lot I keep the horses in, and horse apples didn't last long that way. Then one morning, I was eating an egg, and I swear it tasted funny, so, you can guess the rest.........no more chickens in with the horses.
