?Gape in my pullet

[SanClementeChick]

I have a 3 month old pullet who always has her mouth open. We noticed her start this about 6 weeks ago. She rests with her beak open about 50% of the time and when she runs she always has her mouth open. I looked up videos of Chickens with Gape worm on the internet and they were all in distress. She does not shake her head or cough. She does not appear to be in any distress. She is otherwise well. She eats and drinks without difficulty and looks very healthy.
The videos showed Chickens in the end stage and I wonder if this is early. I have never wormed any of the girls, my original flock (one leghorn and one australorp) 3 years old are in good health. The 3 new girls are 14 weeks old. I have read that Thiabendazole is the recommended treatment.
One of my old girls has started to molt. I have 2 questions does anyone have any idea what this is? I figure it wont hurt to worm them except one of my big girls just started to molt, is Ok to worm them during molt? I don't want to stress her too much. Thanks for any thoughts.

 

[BuffOrpington88]

If you don't want to worm all of them, then you can just worm her by separating her for a day. Fenbezadole would work.