This^^^ but block all the nests.Can we get a picture of your set up? Where are the roosts are as oppose to the nest boxes? Roosts should be higher than the nest boxes.
Rule of thumb is 4 hens to 1 nest ... Figure out their favorite then close off the rest.
First make sure your roosts are easily accessible, of adequate length for all your birds, and about 12" above the nests.
Block nests an hour or so before roosting time.
Open them back up after dark when you lock up or very early in the morning.
I rigged a permanent hinged cover, easy to use and it's always there if I need it.