I have an 8 year old hen who has stopped eating (mostly) and has thrown up white/clear mucus quite a few times after not eating or drinking anything. I thought maybe sour crop at first but there is no smell and her crop is not bulging more than normal. I’ve been getting as much food in her as I can and she seems like she wants to eat but she’s wasting away and hardly weighs anything now. Any ideas what this could be?