Don’t be concerned yet. The internal egg making factory is pretty complicated. Sometimes pullets just starting to lay have to work out some kinks before they get everything right. You might see all kinds of strange eggs, soft or no shells, no yolk, no whites, double yolked eggs, exceedingly thick shells or dark shells, all kinds of things. Most get it pretty close to right to start with but some take a week or two to straighten things out.
About a week before they start to lay most pullets start looking for a safe place to lay. That’s when you are likely to find your nests all scratched up and maybe even your nesting material on the floor. They are checking it out. But some pullets act like they have no idea what is going on. They drop their first egg wherever they happen to be, from the roost or just walking around the coop or run. Once they gain control of that process they will lay in a nest somewhere. Since you have older hens showing them where to lay that will probably be your nests, but not always. They tend to like to lay where other chickens are laying so try to keep the accidental eggs cleaned up so they think that is a good place to lay.
I don’t know how you are feeding your flock. As you know they need a certain amount of calcium for the egg shells. If all they eat is Layer that should have enough calcium for the egg shells, but if they forage or you feed them treats offering supplemental calcium like oyster shell on the side is a good idea. But when pullets first start to lay, their body may not use the calcium they eat properly. Their instinct to eat the excess calcium has to kick in too. I think offering oyster shell on the side is a really good idea for practically all our flocks, whether it is needed or not. If they don’t need it the oyster shell can last a long time. But it may take a while for a pullet to work out all the kinks in her system including realizing she needs the extra calcium.
I did have one pullet that never gained control and would consistently lay an egg from the roosts. This went on for over two months before I finally figured out which pullet is was. There was something wrong with her so I removed her from my flock. But that is only one pullet out of all the pullets I’ve raised. Give them time. Practically all of them gain control and lay right pretty soon after they start. As complicated as that egg making factory is maybe the surprise is that so many get it right to start with.
