4 week old Polish, droopy head, wings and tail

[LaFleche]

Wouldn't the crop be enlarged if it was impacted?

It can be enlarged and squishy/fluid filled or rather like a hard ball. If you are unsure, you could separate her for the night on a towel in a crate without feed or water, to see if the crop emptied completely overnight.

Did you open up her beak to see if something is stuck in her mouth cavity or farther down her throat?

 

[LaFleche]

In this video she is sneazing heavily, it even propels her backwards. So a respiratory infection might be possible.

Could she have ingested a poisonous insect or been bitten/stung by one?

 

[Chickenaddiction2021]

It can be enlarged and squishy/fluid filled or rather like a hard ball. If you are unsure, you could separate her for the night on a towel in a crate without feed or water, to see if the crop emptied completely overnight.

Did you open up her beak to see if something is stuck in her mouth cavity or farther down her throat?

As stated, her crop is empty.