What age can chicks have a perch?

[Rainier]

We got 10 chicks (five of which were banty chicks) and 10 chicks from a co-worker. I put a branch from the yard across the brooder and most of them were up there roosting by the second week. The only one that doesn't get of up there and roost is the silkie chick. The chicks ranged in age from 1 day old to 1 week old, and I think one might have been 2 weeks old. All of them are thriving and doing well. We just moved them to the big girl coop (although we do have a couple of roosters) and it was the funniest thing to watch. They all hopped and flew around. One would start and then the rest would follow, it was crazy. Got lots of happy clucks from them.

 

[kenguy]

Well the strange thing about my chicks, Maran Wellsomer crosses raised by their Maran mom, was that my old countryman neighbour warned me not to allow them in the big chicken house too early because they will want to perch with their mom.
Sure enough they both developed a hunched crippled shape just as he warned me, and both pullets died as young adults while running in the free range. I felt upset as well as feeling a fool.
I don't understand it myself for as was rightly posted above, I would have thought nature intended them to get up into trees for safety at a very early age.
I have a batch of Marans three weeks olds now with their mom, and want to free up the brooder pen for the next lot under a silky brooder hen, when they hatch later this month.
I have just moved from incubator to natural adopted mother brooding, so I want to move the family into the main run as soon as I can.
Saves me keeping them separate and raising them myself until they are 3 months old as I have been doing.
Anyone know when it will be safe to let the new family join the flock??