Thank you both so much! Yes it's very hot here and they pant, but what I'm seeing here is definitely gaping. Neck stretches straight up, opens mouth wide, almost like a upwards gag. She actually started gaping a few months ago, but it was infrequent. When it progressively got worse I wormed with Safeguard liquid (about a month ago). But I'm not sure how effective it was because the wormer always just settled to the bottom of the waterer. Gaping has since worsened more and now also head shaking and ear scratching. So I now tried the ivermectin.
I'm not sure I can manage the q-tip test. She will struggle and I'm afraid I'd go down the wrong hole or something. If I can't figure this out another way, I may try it though. I am starting to doubt that this is gapeworm because there's no wheezing or anything like that and it's been going on for so long, she'd have probably succumbed by now.
About ear mites, I too suspected that. I was hoping the ivermectin would kill ear mites? I have already searched until I'm cross-eyed for info about ear mites in chickens or birds and can find virtually no information. I'm wondering if a pyrethrin based ear mite cream for dogs might work and be safe. This all started with gaping (and slowly worsened), but would ear mites cause gaping? I'm thinking yes, but I'm not sure. Ironically, shortly after the gaping first started a few months ago, I also noticed the 'fur' patch over her ears lightened to a brown color, but I didn't even know that's where her ears were. I only noticed them now because she has scratched a lot of that 'fur' patch off and I can clearly see her ears. So even though the first symptom was gaping, I think you're right that the ears have been the problem all along.
Sorry this got so long, I wanted to provide further details and see what you think. This means the world to me, thanks so much to both of you for helping me try and figure this out for my little bantam BR. She's a very sweet girl. And if anyone can help me find any info about ear mites in chickens, please please let me know.
ETA: I guess I was typing this post while you were adding that info. You sure found more ear mite info than I did, thank you! So I take it that ivermectin doesn't kill ear mites? If she's still no better tomorrow I'll give olive oil a try. Could these ear problems also be the reason she hasn't laid in so long (going on 2 months)?