Slipping them under has worked for some and not for others. All you can do is to try it and be prepared with Plan B if she doesn't accept them. Put them under her at night while she's sleeping. Make sure you are there when she wakes to protect the chicks if she attacks them.
Good luck!
I had my first broody hatch her chick three weeks ago. Yes, she will take care of it herself. She will keep it warm and teach it to find food on the ground (if given access). It's so sweet to see my hen kill a worm or grasshopper and then call to her baby to come over and eat it.
I kept...