Six years may not seem old for breeder stock, but for hatchery production type hens, it's positively ancient.
This stupid heat is affecting Nugget, too. She and Reba have been having terrible issues with it and both of them are having breathing problems today so I put Nuggs up in the cage with Reba in front of the fan so she could stay still and cool. Nugget is super fluffy, being a huge breeder quality Buff Orpington girl, going on four years old now, and a couple of times, I thought she was going to die on the nest, her panting was so extreme.