What's wrong with my brown sex-link hen?

[MeganMarie14]

Lily, the chicken I've been worried about recently has become very lethargic. She won't come down from her roost in the morning, I have to help her down. I'm not sure if she's been laying eggs, but I've seen her in the nesting boxes. She seems to be eating normally, if a but less. She's been drinking her water fine. She's about 2 years old. She'll just stand in random places in the yard without moving. But she doesn't hunch over like she has a bad egg in her. I don't know what could be wrong? I'm a bit younger and don't know much about illnesses chickens can contract. Please help!

 

[Eggcessive]

Welcome to BYC. Sometimes it can take some time to figure out what is wrong with them. Mostly, it involves checking out everything physically. At her age reproductive diseases can cause problems. Internal laying, egg yolk peritonitis, salpingitis, cancer, and ascites (fluid collecting in the belly,) can sometimes affect them. Feel of her keel bone (breast bone) for any loss of weight compared to the others. Feel of her crop in the evening when it should be full, and in the early morning, when it should be fairly empty. Look her skin over around the vent, under wings, and around the neck for lice or mites, and their eggs. Does she look sleepy or alert? Try feeding her some chopped egg or canned tuna. Place her on the ground, and see if she can walk normally, or if she waddles, stands more upright, or limps. Look at her foot pads for swelling or dark spots. Notice if she has any respiratory symtoms such as sneezing, gasping, or eye/nasal drainage.Here is some info on reproductive disorders:
http://www.chickenvet.co.uk/health-and-common-diseases/egg-laying-issues/index.aspx
http://scoopfromthecoop.nutrenaworld.com/tag/laying-issues/
https://www.backyardchickens.com/t/526089/egg-yolk-peritonitis