So i've decided to worm my chickens for the first time and I went to tractor supply to get a wormer. I wanted to get Valbazen because apparently it kills all the worms chickens can get. I didn't find it so I got Ivermectin instead. I'm now wondering if I should worm with ivermectin first, get some valbazen online, and then worm them with that in a week or so, or will they be fine? Or should I just skip the Ivermectin and wait for the Valbazen? Or if I use the Ivermectin should I repeat in a week or two weeks? Please help if you can!