ten day old chick gaping her mouth and shaking head

[Jastorm]

I'm a newbie, starting a five hen flock of Productions Reds. They are from a hatchery in the Pacific Northwest and I bought them from a third party. The chicks are twelve days old now and I've had them since day 2. They are under at heat lamp at about 90 degrees, fed chick starter crumbles, fresh water and are on crushed straw over newspaper. There is ample room to move and the girls prefer to hang out at the end of the brooder near the heat, but they are never huddled tightly together.
One of them looks more bedraggled, she holds her head closer to her body, her wingtips hang a bit lower, she is smaller and a bit lethargic. She does have more advanced feather development and very long primary feathers compared to the others! She eats and drinks well. She did have pasty butt on day 2, but it cleared up as soon as I treated it. I've given bits of boiled egg yolk which she loves.
Today I noticed her have a few spells of stretching her neck out, opening her mouth wide, and then giving her head a quick shake over and over again at about ten second intervals. I would not say this is simple yawning, as it went on intermittently for an hour each time. Could this be a concern or perhaps just a bit of straw in her gullet? I've read about gapeworm, but she does not seem to be having any breathing issues. Would gapeworm affect chicks so young? Thanks for any ideas you may have!

 

[Mamatomany123]

Have you felt her crop? It sounds like something is stuck

 

[Jastorm]

Thanks for the suggestion! I have felt her crop but don't really know what I'm supposed to be feeling... she is no longer making the yawning motions this morning. But she is definitely "off", standing quietly apart and unenthusiastic about food. I guess time will tell. If possible can you tell me what her crop should feel like?

 

[Mamatomany123]

It should feel soft. Does she have pasty butt? Is she eating?

 

[Jastorm]

No pasty butt... her crop feels like the others'. She is a bit more lively just now, so probably on the mend. Thanks for responding! I probably spend too much time obsessing over their health and whether or not I'm taking good care of them!