"Going Broody" means a hen is wanting to hatch some eggs. They get that way whether there is a rooster around or not. In some cases, they will go broody and there won't even be eggs to hatch. Typcally they will stop laying and start sitting on the eggs( or on nothing, if there are no eggs). They may lay flattened out- look kind of puffed up. They might growl or scream if you try to touch them. They may also pull out their chest feathers ( to keep their skin against the eggs to keep the eggs warmer) Their body temperature may go up a little also.