First time hatcher. So many questions!

[dixie1024]

I've never hatched eggs before, and we're fairly new to chickens in general. A few weeks ago we went on vacation and had a friend checking on our chickens. He left the eggs in the coop so one of our hens started sitting on them. (We have 3 chickens-mama, her son the rooster and her daughter the other hen). Mama is on the eggs. Sister likes to lay her eggs in the spot mama is sitting. I keep telling my husband we need to mark the eggs or stop sister from laying there but he doesn't think it's a problem. Now mama is laying on 18 eggs (she's a buff orpington). Once the first chicks hatch, will mama continue to sit on the eggs of the non hatched or will she abandon them? Help!

 

[LittleGecko]

Your mother hen will continue to sit for a few days after the first eggs begin to hatch but if her cluch gets too large there will be losses as she can only sit so many eggs at a time and when the earlier chicks get more active she will leave the nest to care for them. Also the larger older chicks may bully or out compete the younger weaker chicks if the age gap is too large.
I have two hens sitting on eggs right now and they also take the eggs my other hens lay in the nest box, but I have marked the hatching eggs and so can remove the fresh layed eggs each day from under the broodys. It's better to only hatch a set number of eggs as all those chicks are gonna take up a lot of room as they grow up and you don't want to hatch more than you have room for!
Your first hatch will be really exciting and I hope it goes really well for you and your chooks!
Good luck!