Might I suggest you read this thread. I think it will help.
Isolate a Broody? Thread
https://www.backyardchickens.com/forum/viewtopic.php?id=213218
The other chickens like to lay in a nest where there is a broody and a broody hen will normally accept any and all eggs she can get. Nothing unusual at all in the behavior you've seen.
How do i make her more comfortable?
As mentioned in the above thread, you can either isolate her or not. People are successful both ways and chickens have been hatching eggs both ways for centuries. There are risks both ways. The hen right now is not worried about being comfortable. Her hormones have her thinking of nothing but hatching eggs and raising babies. If you isolate her, make sure she has access to food and water and a place to go poo whenever she wants to get off the nest, which is probably once a day. If you don't isolate her, I'd suggest tossing her off the nest once a day when you check for new eggs, preferably late in the day but before dark. She'll probably eat a bite, get a drink, take a poo, and maybe take a quick dust bath before jumping back on the nest. Other than this, the less you bother her the better and more comfortable she will be.
Do i have to do anything when the eggs hatch?
You do not have a normal situation since eggs have been added. I'll get to that in a minute. Normally, you have a decision to make. Do you let her raise them with the flock, do you isolate her and her chicks so she can raise them away from the flock, or do you take them away from her and raise them yourself. People have been successful for centuries doing it all three ways.
Since eggs have been added, you will get a staggered hatch. You have some options, none of them real easy. You can just let her go and when she decides to bring the ones that have hatched off the nest, accepting that the others won't hatch even if they were developing. You can do the same but try putting any eggs left in an incubator or hatcher, trying to get more chicks. To me this is the most risky but people have done it. You can remove the chicks as they hatch and dry off, put them in a brooder, and raise them yourself. If you remove them as they hatch she may stay on and hatch the others. After 21 days from the last day that a new egg was put in the nest, you can let her keep and raise any chick that hatches. You can even try to give her back any chicks to raise that are only a few days old. There is a pretty good chance she will accept and raise any chick that is only 2 or 3 day sold if you slip them under her at night. But you will wind up raising some yourself and they will be of slightly different ages. It's all doable but messy.
What can i do to get a better hatching ratio?
If you are going to let a hen hatch the eggs for you, save up all the eggs you want her to hatch, mark them so you know which they are, and start them all at the same time. Remove any new eggs that find their way into her nest.
Hope this helps. The situation is messy but not hopeless and it is a great learning experience for you. The next time should go a lot smoother.
If you want to, you can tell us the breed of the rooster and hens or post photos and we might be able to tell you what the chicks will look like.
Good luck!!!
