My 10 month old bantam brahma just started frequently opening her mouth while stretching her neck only slightly. I've looked up gapeworms, but don't see any of the other symptoms (head shaking, sneezing?, tired & not eating). 1) Could this be an early sign of gapeworm and then be easier to treat? 2) If not, what else would cause this behavior? 3) If it is early signs of gapeworm, how do I treat it? (I've seen recommendations for Ivomec, Flubendazole in feed and levamisole, and a topical medicine?) 4) Would I treat all chickens? 5) If treating, and for now not knowing if worms, should I not eat her/& their eggs? I've read posts where the meds don't work and the chicken would still has the symptoms while getting worse...is this a common thing and can I avoid this? Thanks!