I've got some young (8 week) old chicks but they're not old enough yet for me to tell much about their attitudes. I will say though that most of them (Easter egger especially, but also olive egger, wyandotte) are way more flighty than my 2 1/2 year old RIR hens were at that age. The barred rock and the rhode island blue chicks seem more mellow. Maybe I am spoiled by RIR. I've heard them described as bomb proof and that is mostly true. Not much upsets them for very long. Truck/tractor pulls in the field next door, running the mower right next to their coop, the neighbors dog trying to play with them, fire works etc has never resulted in a slow down in laying or acting like they were stressed after their initial surprise. I've found RIR hens to be friendly, very inquisitive, interactive and well behaved. I've never had any be aggressive or mean. A few are even lap chickens. (RIR roosters on the other hand can be real jerks from past experience). I've been around White Leghorns growing up too and they are just the opposite. Very flighty, unfriendly and somewhat mean.