I have three batches of chickens ranging from three years old to a new batching from March. The first flock layed well and continued until approx one month after the second where introduced. Over the years the egg production has diminished and stopped. Even the new flock isn't laying yet. I have added light for extended days, put live traps to catch any wild life (haven't seen any signs), changed the food, added a rooster (whom was active and now stopped mating and crowing), checked for broody hens ect. I did an examination of the dead bird and found no parasites. Suggestions?