I don’t know what your set-up looks like or how you are managing your chickens. I don’t know how high your nests are. I don’t know of you have “regular” chickens or some exotic breed that cannot fly. I don’t know a lot about your situation so I can’t speak to that. I can tell you that when my broody hens hatch, I leave them alone. I let the hens decide when to bring the chicks off the nest. I’ll have food and water where the chicks can get to them but other than that, I let the hen raise them. I don’t know how you do yours but I let my hens hatch with the flock and raise the chicks with the flock.
I’ve seen a hen get chicks out of a 10’ high hay loft. Mama flew to the ground, said jump, and they did. Then they bounced up and ran to Mama. My nests are not that high. The bottoms of the openings on the lower ones are a bit over a foot off the coop floor, the others about 2-1/2 feet off the floor. My hens have absolutely no problems getting their chicks to the coop floor when they decide the hatch is over.
Not all chickens are consistent. I have seen a couple of hens try to take their chicks to a lower nest to spend the night. Not the nest they hatched in, another nest. When the eggs hatch they leave debris in the nest. It will smell after a short while. If a hen took her chicks back to the same dirty nest, predators would easily be able to find them. Mama’s instinct is to find a safer place to keep her babies. One was successful in getting her chicks to jump up that foot or so, but the other hen’s chicks couldn’t all make it so she abandoned the nest and took her chicks to a corner of the coop to spend the night on the floor. That’s what most of my broodies do anyway, just keep the chicks on the floor of the coop at night until they take them to the roosts, usually in a corner.
Something else I don’t know is if your hens are all sharing one big nest or if you have them all in separate nests. I don’t know if each broody is isolated from the other broodies or the entire flock. People do this all kinds of ways. Many people are quite successful in having multiple broodies hatch together and raise the chicks together. But, as I said, they are inconsistent. Sometimes broody hens fight over the chicks or eggs to see which one gets to raise them. Chicks or eggs can be damaged in these fights. Sometimes when a hen hears chicks hatching in another nest, she abandons her eggs and goes to the chicks that are hatching, either working with the other broody or fighting her for the eggs and chicks. Her abandoned eggs don’t hatch unless you do something with them.
One time I had a hen go broody just a couple of days before another broody was due to hatch. The chicks were peeping inside the shells and had not even pipped but the second broody heard them. Those hens fought over the nest and destroyed half the eggs. I’ve also had hens bond with their own chicks and leave other chicks and broodies alone. But after that I don’t let two broodies in different nests hatch in the same coop, whether at the same time or weeks apart.
I am not saying that you are absolutely without a doubt 100% sure that you will have problems. As I said, they are inconsistent in what they do. But you have a potential for problems. I suggest you have a plan B ready if you see fighting or abandoned nests.
If it is important to you for them to sleep in the nests you can probably train them to go in there. Just lock the broody and her chicks in the nest overnight, then let them out the next morning. After one or two nights she’ll probably take them to poop in the nest overnight on her own. You can build steps or ramps of about any kind to help the chicks get up there. If they fall off it won’t hurt them. They’ll just hop up and try again. Chickens are not always the best at figuring out logic problems. If one falls off and Mama is in the nest right above telling it to come here, it may not know to go around to the foot of the ramp and try again. It may just stand there peeping “Mama I want to come but I don’t know what to do!” So I suggest you be down there around bed time to give help if it is needed. They should figure it out in a few days.
But personally I let my broodies raise their chicks with minimum interference from me. I do less harm that way.