Hate to spoil the party, but I had 2 broody mamas this summer (bantam Mille Fleurs) who shared a pile of eggs. They shared the chicks, too.
BUT---They hatched 2 of them, then abandoned the rest. It was sad, there were so many that were viable. Next time I will move the whole lot to the bator soon as the girls stop brooding the eggs. I think they figured after 2 they were done. The chicks (barred rocks) are now bigger than their mommies (I like saying 'they have 2 mommies!!') and still follow them around. They have made palsy walsy with the girl's new boyfriend, a little Mille rooster. It's a little banty family.
I kept them on the floor in my beat up old brooder box (which is now in the fire pile)
that I made years ago so they could be safe (with the top on) with food hopper (with starter) and waterer in there with them. Safe from the other chickens, of course. Everyone was content. After a couple of weeks, I took the lid off and they all came out (with a box inside so the shrimps could hop out with the mommies).
Mommies escorted babies all over the yard, it was super extra nuclear poison cute!!!!! The babies would go outside the fence, of course, they were so tiny but never, ever run off. They'd just go in and out of the fence, keeping watch of the mommies and sticking around-- until one day they just couldn't anymore (from growing).
They would go up and down the ramp into the chicken house, with the mommies. Mommies would each take turns defending the chicks against big chickens who may hassle there. Mommies are tough with great bad attitudes!
The chicks learned to deal with everything, all the other chickens and are now parts of the flock. They even hang out with the adult barred rock girls.
Don't worry so much. If your girls have instinct enough to set on eggs naturally, they have instinct enough to raise their kids correctly, just like in the cartoons.
She's such a sweet little hen! She does look like a black pancake with a head though
