Thanks viettaclark for your reply. This particular hen has been broody many a time when she stops laying and won't leave the nest box, after leaving her in the sin bin for three or four days it normally brings her out of it and she's back to normal, but this time despite the sin bin and normal procedure for a broody hen, she's definately acting strange. Never known it to happen with any of my broody hens before and certainly never had it with her. She's always been a good hen although frequently broody but never no trouble to bring her back into lay. Could she be egg bound I wonder?