Leghorns can be quite feisty I find. Never the calmest of birds. Also be careful if putting them in pens with low sides as they will fly and they can get quite high and go quite far. I've had them fly well over my head before. Wing clipping helps. They do calm down after a year or so though and are then generally normally behaved hens. I've got a cockerel who attacks me whenever I go into the run at the moment and stalks me up and down the fence if I walk by. Unfortunately for him, his replacement has just started treading.........