Oh... That's not where the air holes should be. Not the only air holes, at least. There are rules for what containers can get approved for mailing chickens.
🤔 Now that I think about it, I vaguely remember there being some specs for crush resistance too, so maybe stacking is normal practice?
I used to ship lots of things, but never animals, so my knowledge and memory of this is pretty fuzzy. Seems like some rules were broken to end up in that situation though... which still sucks