Bugaboo,
I handle the chicks in the nest boxes from the first week of life. I will clip a few wings and continue to train them. The others I do not clip their wings unless someone want them clipped when they buy them. The reason is that I have a friend that buys them for her training sminars and am so blessed to have her in my area. She works only with flighted birds. Linda is an awesome positive reward trainer... chek out her site
http://araptero.com/
I am getting ready to have a sale on some , breeder pairs for spring because I have a surplus of hens. Some of these are getting a little age on them...5 months and becoming a little snippy. Most people wanting a pet usually pick a male.
So yes, some remain tame...some start to get a little birdy.