She's brooding, pginsber. I have never had success in breaking them by just tossing them out of the nest every so often. Usually, what I do is set up a dog crate or a similarly sized cage in an area that gets lots of chicken traffic, so it isn't private or very quiet, and then I keep the broody in that cage during the day until she gives up. At night, I make sure she goes to roost and doesn't sleep in the nests. I sometimes have to block the nests in the evening for this to work. My girls take one, maybe two weeks of this before they quit brooding. The other option is to get her some fertile eggs to sit on, but personally, I don't have the space and don't like to add extra birds unless I'm sure they're pullets. ETA: Oh, and about the egg, it is possible that it's a double yolker--they happen more often with hens that are just starting to lay. There's no way of knowing for sure without cracking it open, though.