I have silkies who go broody before they ever even lay an egg or lay for a couple weeks, then they go broody. Every girl is different, some just 'think' they want to be broody, some are serious stubborn broodies that will sit on air in hopes of having babies, some just want to sit eggs and don't make good mothers, some want babies so bad they'll sit on eggs for a couple days then still another hen's chicks, or even take up chicks that are 4-6 weeks old that the 'real mama' kicked off...
I say give her a few days of sitting on golfballs, plastic eggs, or just spare eggs you have (that may be infertile even) to test her out to see if she is sticking to the idea of going broody. Then give her some eggs if you want chicks. if you don't want any chicks then try and break her of it. (lock her out of the coop, put her in a cage with a wire bottom no bedding, dunk her in cool water atleast once a day as well and stick her in the cage to 'cool her bum' and try to break that 'broody switch'
