This is in NO way an answer to your question. I'm just sharing my experience. And this is my very first experience with broody-raised chicks.
That said, my chicks are about 2 weeks old. They stayed with their mama hen in a nesting box in the coop originally. While they were up there I provided food and water. When they followed her down to the run a few days ago* I was at a loss. I tried to provide food and water for them in a quiet corner but when there's something new, everybody is all over it! So that wasn't working.
I wrung my hands thinking they'd starve. They haven't. They're growing and thriving. On what, exactly, I have no idea but it's fun to watch them follow their mama around and scratch in the dirt of the run just like she does.
When I put out overgrown squash or whatever from the garden they may have to wait their turn but they manage to peck away at what the older hens leave.
I'm amazed how capable they are right from the start!
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* I'm in SoCal. We're up to the high 70s and 80s already. We've even had some triple digits.