Sounds like she is laying a clutch. There are probably a dozen eggs waiting for you somewhere.She's been doing this for a couple weeks now. Its between 9am-1pm. I search ALL the places she could be. I am thinking she is in the brambles somewhere laying eggs. Now I have to look up GPS collars for chickens! Thought about a GoPro.
Speaking about chickens.. I am considering making them saddles. Poor girls are bare back and the back of their heads. Doesn't help that my rooster takes his SWEET time making sweet love (sorry couldn't help it, lol).
When I was a kid, hens would "disappear" only to return with a bunch of fluffy chicks. They were great at hiding considering all the predators we had.