Since mine watch the grown hens they learn to lay eggs in the nests. So since the nests are open to the older hens, they are always open to the pullets. However, as soon as I open the grow out pen and allow the pullets to mingle with the flock full time I watch to see if they are looking ready to lay. Generally, about the time they are big enough to integrate, it's about the same time they are ready to lay. Every night after the pullets are integrated I go out at dark and make sure that everyone is sleeping on the roosts, not in the nest boxes. My first 6 hens that I started with were obtained at point of lay. They had never been given a roost and forever, no matter my best tries, slept in the nest boxes. I had poopy eggs until the day I re-homed them a few years later due to age. I will NEVER let another chicken sleep in a nest box!
