They'll typically start coughing and will develop pneumonia or a wheeze very quickly. If it gets in there, there's really not much you can do about it except treat with antibiotics on top of the handfeeding to try and fight off the pneumonia.
We are as gods to the beasts of the fields. We order the time o' their birth and the time o' their death. Between times, we ha' a duty. - Terry Pratchett.
"Men have forgotten this truth", said the fox, "But you must not forget it. You become responsible, forever, for what you have tamed. - Antoine de Saint-Exupéry