Broodie or stuck egg? Help!!!

My RIR hen does this. She will sit in the nesting box half the day to lay an egg. Then as soon as she is done off she goes. Just keep an eye on her.

 

Will they come and go before laying? I have a hen here and I am no positive she is laying yet but the other day she hung out in the nest tucking herself all in with hay and then when she left, no egg. Today she was pacing around in front waiting for the other girls to lay and then when one came out she went in and sat on her egg and golf ball, moving the ball all over underneath her and tucking the hay around her. When she finally came out, no egg again. Just the other hen's egg. Could she be going broody or getting ready to lay as well? Seems healthy in every other way. Kinda cute watching her do all this. Just don't want her going broody at 23 weeks old. Oh, and she is a Buff Orpington.

 

If she is still sitting there tomorrow try giving her a couple eggs to sit on and see what she does. That's what I finally did at 6:30 this morning. Put 3 bo eggs under silkie, one only half under her. Came back an hour later and she has them all tucked so tightly under her that it would take a jackhammer to get them out now. Broody.