Ive handreared alot of baby birds, and they have airholes behind the tongue, i would expect hens do too, so do make sure to avoid them. Id imagine though if it has gone the wrong way her breathing would be hard and wheezy, and very uncomfortable - and tends to lead to pneumonia in little birds and lambs so prob in hens too You would have noticed that. If the hen has water down into its lungs a vet should give it antibiotics which may help, baby birds it definitely helps. My vet would most likely give her a steroid injection (I think that is what it is), antibiotics and possibly a vitamin boost. These things can all pick an animal up health and energy wise. Ive had an old hen similar, and she came right quite quick after vet treatment. But I have learnt that often for some reason hens are hard to get back to good health once they go off their food. An odd suggestion, but someone told me to try it and it worked- try fresh tomato, they love them, and plenty moisture in them. good luck to you and Emily