I remember reading about a device called a trap nest, that a hen can enter but not exit -- used by breeders who need to know exactly who lays what and to keep records of laying.
IIRC, the book it was mentioned in stressed that it was CRITICAL to check the nest frequently so that the hen didn't suffer from stress or heat.
IIRC, the book it was mentioned in stressed that it was CRITICAL to check the nest frequently so that the hen didn't suffer from stress or heat.