I agree with opening the nest now. When a pullet first starts to lay she may drop her first eggs about anywhere, from the roosts or just walking around. Most have control of that first egg but a lot don’t. Where that pullet lays her first controlled egg normally becomes her nest. I much prefer that first controlled egg to be in one of my nests instead of somewhere else like a corner of the coop under the roosts or some well-hidden location away from the coop.
It’s not that unusual for chicks to sleep in the nests before they make their way up to the roosts. I think having lower nests makes this more likely. I’ve had brooder raised chicks start using the real roosts anywhere from 5 weeks old to several months old but the normal age for mine as long as there are no mature chickens on the roosts is between 10 and 12 weeks. When I have older chickens on the main roosts is when they can really be delayed in starting to roost. I’ve seen a broody hen take two week old chicks to the roosts so this timing can be all over the place. Anyway, the point is that your pullets are beyond this point. They are used to sleeping on the roosts and should remain there as long as the roosts are not too crowded and are higher than the nests. Until they are ready to roost they tend to sleep in a group in some protected place. That is often a corner of the coop but it could easily be a nest, especially if it is low to the ground. A nest is supposed to look like a protected place.
Often about a week before she starts to lay a pullet will look for a safe place to lay. She will investigate different places and scratch around. I fully agree with putting fake eggs in at least some of the nests to show them where to lay. I’ve found that to be tremendously helpful, even with established layers, but someone recently posted that they put fake eggs in some of their nests but left a couple without fake eggs. Their pullets chose the empty nest. You are dealing with living animals so none of these behavior things come with guarantees. Sometimes they will make you pull your hair out with frustration. Still, from what I have seen a fake egg normally helps a lot. I use golf balls.
When they are investigating where to lay and scratching you may find fake eggs and nesting material on the coop floor. That’s another reason I like the nest open early. If you have a problem I’d like to fix it before they start to lay. The normal fix for this problem is to raise the lip on the nest. If they are going to sleep in the nests I want to fix that before I start to get poopy eggs.
The normal fix for them wanting to sleep in the nests once they are old enough to roost is to either raise the roosts if they are not clearly higher than the nests or expand the roosts so they have plenty of room. Expanding the roosts is more important for mixed age flocks. Since yours are the same age they are going to be highly likely to be able to share roosts. When I’m integrating younger chickens is when I see the need for plenty of roost space. You may need to physically move them from the nest to the roost after it is quite dark to get them in that habit.
Good luck! I know this is long but I really think you are doing OK.
