Update: another hen is dead! Also a broody with chicks. She was okay last night at sunset and dead this morning. No swollen head, no secretions from eyes or nostrils, no torticollis. No signs of an attack or a struggle. Just dead, lying there stretched out on her side, as if she keeled over. Taking her to a necropsy after work.
Oh no!
I'm glad you will be able to have her examined. When you find out the results, if you don't mind sharing with us, it would be appreciated.