Mareks and Lymphoid Leukosis are both considered neoplastic diseases, but with her age, it would more likely be the former, I'd think. Just a guess. And you've already had a Marek's diagnosis. LL usually shows in birds older than what she was.
I'm sorry, Julie.
Maretta is having sluggish crop issues. She is drinking like she's trying to drown herself and sleeping on June's "throne" sometimes. Could be the cancer is progressing. But, she still runs out and about with the hens when I let them roam.
And you can also think about cancers and tumors that chickens can have that are not labeled with a specific illness. I had one that I sent in for a necropsy and the lab actually called me because the hen had a rare liver cancer.