I've taken my hen off the nest so many times I've lost count. She sure is committed. She was sitting in an empty nest because I remove the eggs of course, we have no roos. The other hens crack me up, they dive in her box to lay their eggs if she is outside. I gave her a plastic egg from my kids cooking set. Been over 21 days. I don't have a wire cage to break her in. I guess I'll have to get one for future use. I did just get some new chicks. Would she mother them ya think? Or best to leave them in the brooder. I'm not really set up for all I have going on. 2 8week old pullets in a pen next to my hens and 3 chicks in the garage. I let the hens in with the pullets when I'm around. The pullets hide pretty well so I haven't seen anyone picking on them. Just wish that one hen would get back to laying. I've got nothing for her to lay on so it seems like a waste of her good egg laying time. When you only have 4, 1 not laying really cuts into production.
Are the chicks really young? If so, YES put them under the broody. I just did that with the 7 I got last Wednesday (hatched Monday). Put them under my broody Black Australorp Thursday night. The other 2 broodies are in the buster and since I was not sure Zorra would take the chicks (never having done this before) I let them stay broody in the nests for 2 weeks. They are now HARD cases and will likely be in the buster for a week.
If the nest boxes are off the ground you'll need to make a brooding pen. Stick them under AT NIGHT WHEN IT IS SO DARK YOU CAN'T SEE A THING. I tried Wed night but it wasn't PITCH black yet though about all I could see was which end was her head. Could be it was my inexperience and fear she might hurt the chicks but we regrouped and were going to go out again later but ended up with a ton of rain and T-storms so we waited until Thursday night.
Stick the chick in under her wing from the back, distract her with your other hand if necessary. Zorra hit my chick holding hand (grab it over the top so it is fully in your hand but easy to release, feet on the ground) but not with the ferocity it would take to break the skin. She settled back down after the first one went in and I put in the second. Waited a few minutes and put in #3, etc. We did have a flashlight to give just enough light to see, don't shine it at the hen AT ALL, just get enough "edge light" to make sure the chick gets under.
Took this picture the morning after I put the chicks under - 4 days old:
Took this picture today - 8 days old:
If you do not decide to put them under the broody, she needs to go in the buster. Head over to the Mama Heating Pad thread:
https://www.backyardchickens.com/t/956958/mama-heating-pad-in-the-brooder-picture-heavy-update
to see a FAR better way to brood chicks than under a heat lamp. As you can see from the first picture, they DO NOT need to be kept hot for a month. It hasn't been over 65 in the barn and they come out from under Zorra a LOT. And they are a LOT quieter than Zorra and her "sisters" were when I brooded them under a heat lamp in the house for a month per conventional wisdom.