Coopchick, the Ivermectin will treat both the mites and some worms. Is the worm round? It's not a flat tapeworm, is it? I hear tapeworm is harder to eliminate. Supposedly, if you have never wormed before and suspect a heavy worm load, people suggest starting with Wazine. I've never done that. I used Valbazen, as recommended by SCG, along with Ivermectin because mine had mites too. Not sure where you live, but you are welcome to have some Valbazen.
I found worms on the poop board recently, but no one is acting sick. I'm trying to hold off on worming them because they are mid-molt, but hope to do it soon. I would treat my whole flock. I think all wormers have a withdrawal period.