Ah, yeah, there is an old FAQ which answers your question, but, short version-- birds, reptiles and fish are not sentient in the same way as mammals in the story. :]
Teagan Gavet
2019-09-03 15:29:16 +0000 UTC
If you check on the comic's own upload page (which is outdated by now, but w/e), Teagan wrote an FAQ up there that at least marginally touches on the subject, but tbh, I suspect we'll be getting an in-universe explaination one of these days.
Lauri
2019-09-03 15:13:43 +0000 UTC
Interesting tolerance the locals seem to have for "Egg's" diet. The donor's must not be under Oren's protection, or could there be some other arrangement?