is my chicken broody

Although it is a strange time of year for it she may be going broody. 

Does she fluff herself up and get all grouchy when you try to touch her? 

Is she eating, drinking and poohing OK?

Have you wormed her?

Does her comb look red or pale?

This info might help get an answer.

In the meantime good luck 

sounds like she could be broody then

It depends on what you want to do.  You can leave her broody which might put the other hens off laying or you can try some anti-broody measures.  Broody hens can be quite stubborn about it    I had one that I thought was going broody a few days ago but she seems to have decided against it.  You may want to leave her a few days more to see how determined she is.  There have been several good threads about how to put a hen off being broody but I can't find the addresses.