If they are off the ground make sure they can't fall down - it's not the falling that's the problem, it's the inability to get back up to where they fell from - and don't expect day old, week old and even sometimes month old chicks to know how to use a ramp if their mother just flies up. They do stick close to mum, but they can run like billy-o on day two and anything that spooks them could see them run right off the edge of a shelf.
She'll eat the chick feed and ignore her own food probably - little chicks do love a mushed up COLD boiled egg and so will mum. All that sitting around is hungry work !
My top tip for expectant mums (i.e. you, not the chicken) is not to be over eager to check if they've hatched. Don't keep lifting her up from June 7th onwards hoping to see the first chick. If you go near her you'll hear the little ones cheeping under her and you might see an empty egg.
You might also see a pipped egg with only a beak protruding - now you are wandering into a dark place.
How long has it been like that? - Will it get out by itself? - If I don't help it and it dies in the shell will I feel guilty? - If I do help and it dies once it's out the shell will I feel guilty? - If I help it and it dies, would it not have died if I'd left it alone?
The real top tip here is - do nothing - a chickens job is to hatch eggs and rear baby chicks - that's what they are designed for, let her get on with it. If some of them don't make it then that's just the cards they were dealt. You can keep one extra alive by intervening sometimes and it can be very rewarding, other times you get the tiniest of little chicks take it's last breath in your hands and you wonder if you perhaps shouldn't have intervened.
I find that by not intervening at all, the easiest person to blame for any misadventure is good old Mother Nature. It's also easier to explain to your children.
I hope you send some photos in of your first clutch.
Although we have them almost constantly it's still a delight to see half a dozen little bundles of fuzz appear from under their mum.