I'm so sorry for your loss. Several of my young chickens have died over this last year. One I think she was egg bound early this year, two I lost I'm pretty sure to the horrible summer heat, and one just now. No trauma, no runny nose/eyes but her belly is bald. This time though I found her before she died so did the only thing I could think of, put her into a warm bath and checked for an egg, found none. I'm thinking I should pay for a necropsy. I bury my pets in an old blueberry plot, deep so no one can dig her out. I send with them crumbles and treats, maybe they'll come back as a cantaloupe. I hear chickens can just up and die, but then I read that they live for 8-10 years. It's hard when something you care for every day dies and you don't know why. My heart goes out to you and your little chicken. Love the rest, life is obviously too short.