I've got a mixed breed 5ish year old hen that has been treated with Ivermectin routine. I've not got an issue with external parasites. she's very lethargic and walks with tail down, nasty poop and lies down a lot. She's good for several days and then back to the same issues. Has not laid an egg in months. She pants when she's in this funk but will eat and drink sparingly. I've given her Tylan injection s in past but they make her very very weak. I have no idea what to do anymore She's been going through this cycle for several months. She doesn't have a crop issue and I'm thinking it's more of an internal laying issue of some other cause. Any ideas appreciated