Well, I don't. But by a flip of the same coin, how do I know they don't?
I've seen LOTS of open-mouthed neck stretching, which makes me think of gape worm. I've read it's not that common, but I kind of just have that sort of luck with chickens. I bought the safeguard paste because they say it's practically impossible to overdose them, and with the correct course of treatment it kills every kind of worm.
I've never wormed them, but with our dogs, woods, and wet ground I'd almost be surprised if they didn't. How would wormer react with their gut bacteria? I could dust for mites, give probiotics, and worm in a few weeks depending on how things look.
I agree that they've been through a lot lately. All but the two look great. I even saw the rooster mount a hen today, which is always a good sign.