You really want to curb the habit of sleeping in the nest boxes. When you close the coop at night put empty feed bags in each nest so they can't be slept in. It's a hassle now that you've some birds laying as you have to remove at least one bag each morning and replace it at night. The nests are a natural safe place to be and that's what the birds want, blocking them off before lay will force the birds to the roosts and get them in the habit of that then you can unblock the nests before they start laying. Last thing you want is poo in the nest boxes mucking up your eggs. You must curb that habit asap.