First, a hen has to 'go broody'. This only happens when you don't want them to

JK - but with your new hampshire it should be occasionally if ever - like maybe once a year. Or maybe she never will at all. Also, she will probably only do this over the summer when the weather is nice. Now, if you have a silkie or a cochin, you may have to break their broodiness with ice or cold water here and there.
Anyway, only a broody hen will even sit on eggs, so if you pick yours up ever other day at minimum, you won't get any babies.