I've had two 1yr olds before and it's not bad, just take your time getting them around and it's much less stressful. To the point of only have 1 or 2 that you would have to carry out in an emergency, in the panic of an emergency you would probably have to carry (or at least lead by the hand) every kid there except maybe those 4 and up. Even if a 2yr old can walk 100%, don't expect cooperation during a fire etc.