I think it depends more on how they are raised. I have 6 week old EE's and BR that are VERY friendly, they will all get in my lap and go to sleep and love being petted, but I have spent alot of time handling them, I also hatched them and I think they think I am thier Mom. My current chicks are 12 days old and are BR, BSL and RSL, and they are becoming like the chicks I hatched with the BR and RSL being the very friendliest. Then I have a group of BO that just got here yesterday and I will start handling them today, I wanted to let them rest and regroup after being shippid.
I don't know if this makes any difference, but I always pick the chicks up from underneath, they tend to stay calmer and don't freak out, when I get in a hurry and pick them up from above it is very hard to get them to calm down. I am sure this has something to do with preditors getting them from above ie Hawks.