The general rule is supposed to be one nest box for every four hens. The hens, however, have not read that rule, because I have several coops and the hens prefer to lay where some other hens have laid their eggs. They move around, as if testing different coops. They usually pick one particular nest box in a coop, though. "This is the best one." For a while, they used one small coop with NO nest boxes as a great big nest box and all the girls would lay their eggs there.
Their favorite locations are in large, covered kitty litter boxes on the floor of this or that coop. However, that's usually where one or another of my hens will go broody. So, for the duration of her confinement, the rest of the girls have to lay their eggs in a different location. Two days ago, one of my blue Orpingtons took over a favorite kitty litter box/nest on the back porch for her confinement. So now I find eggs in a variety of nest boxes in various coops.
Makes it just like an Easter egg hunt every single day.
Oh, I have about 25 pullets & hens of all different ages. I can gather as many as 18 eggs a day, 14 large fowl eggs and 4 bantam eggs. There are at least six pullets I know are not yet laying.