Since you moved her, let her settle in for the day, then wait until it's very dark. Pop the chicks under her and see how it goes.
I'd go out fairly early and check to see if she's accepted them. Broody hens can be a bit funny about things at times.
On the note of the snake, you may be repeatedly removing the same one a couple of times a week.
I get Black and King snakes in my runs and in the nesting boxes. I always look and I usually use a grabber tool to reach for eggs.
I've thought about marking the snakes somehow when I remove them from the coop/run just to see if it's the same one. One year I took one to the backside of my property and the stupid thing basically followed me back home. I was a bit creeped out.
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@Miss Lydia mine can get quite large. I had about a 6' King snake in the run last week, he wanted OUT. Then hens and rooster were stalking him
BUT, if I have chicks, they get moved immediately and I watch for them more. Usually this time of year they have left for the creeks, but it's been cool here, so they are still hanging out near the outbuilding and pumphouse where they overwinter.
It's a bit creepy here at times.
I used to have one that lived in an outbuilding for years and years, he was huge, he was more than 6', because he'd lay on top of the building doors and they were about 10'. I always looked up when I went in that building, you sure didn't want him to fall on you from the rafters. Anyway, I don't know what happened to him, he didn't appear one spring so he must've croaked over winter. He was at least 15 years old I'd say.