I have four chickens and they like to sleep in one of their nesting boxes and not the roost that I made for them. They have only been in the coop for about a week. I am not sure if they will when start to roost as they mature as they are only three months old???
At twelve weeks they should roosting. Block off the nests, so they have more incentive to use the roost. Once they get into the habit of using the roost you can open the boxes.
Yes, in a way. They will put out a lot of poop overnight. If that happens in the box, then eggs will be covered with poop unless you clean them out early each morning.
Mine went through the same thing, until I blocked the nest boxes off and placed all of them onto the roosts in the evenings for two consecutive nights. Now, everyone roosts fine except for my BR....who INSISTS on working her way to the TOP of the coop (despite clipping her wings and the peak being narrow and sharp). So we still have to go out and throw her inside every night, but everyone else figured it out and no one sleeps in the nest boxes any more.
I had the same problem and have just learned that chickens feet do not have a gripping action that allows them to clutch onto narrow round dowling type roosts. They need a fairly wide flat surface to the roost about 70 to 100mm maybe 3 or 4 inches. I changed my roosts and immediatly my hens began to roost by themselves. Hope this helps.