I have about a dozen young chickens ranging in age from 16-20 weeks with pale faces. There is also one hen that's over a year old, with a pale face and comb and she's been moulting. I noticed that this hen and some of the young birds were opening and closing their mouths, so I suspected worms. I gave them all a dose of Eprinex pour-on liquid four days ago. I don't see much of the mouth opening and closing anymore. I'm just wondering if I'm on the right track. Is this worms? None of them are having trouble breathing, so I don't think it's gape worm. Do other worms also cause that opening and closing of the mouth, and a bit of neck stretching? If this is worms, when should I see an improvement? The poops look very normal. They're eating and active enough but the paleness isn't changing. I realize that if this is anemia, it could take a bit to see improvement. I didn't like to use Eprinex on the young birds, but felt it was better than waiting it out if it's worms and if they're anemic. I'm going to have to give a 2nd dose if this is the right treatment course to be following for this. There seem to be many different recommendations out there for when to give the second dose. I've read 3 days if they have an infestation, and I've read 10 days, 14 days. What's generally recommended - if this is worms. The hen was broody a few times this spring/summer, and the last time, she wouldn't give up, so may have gone 4 times. I wonder if that weakened her, and made her prone to something, and then the young birds also picked up something. I understand young birds can be more susceptible to worms than older ones. Is that true? Any suggestions, ideas? Am I on the right track? Is there something else that might be going on?