Age to add to flock

Hello, I have another question  . My cream legbars are almost 17 weeks, is this a good age to add then to my 2 ex batts? I have unmedicated growers so could mix the food with layers until its gone. We're putting our house on the market in the next few weeks so i'd like to take down the second coop & run. They've been in the same garden but haven't freeranged together. The ex batts have jumped all over their run etc (legbars a little anxious at leaving their run - new coop is more chicken friendly)
Soooo any advice welcomed 
Thankyou