How old should chicks be before adding to adult flock

I have always waited until the chicks are about 4 months old or the same size as the other birds. I'm sure others do things differently. I also free range my babies after a few weeks (weather permitted) so they get a chance to mingle with the rest of the flock before intorducing them.

 

When I had the chickens in a smaller area, I always waited till they were about the same size also. However, I now have them in a huge fenced in area where there's lots of room to roam and I have put in some small ones (as young as a month) and they are fine. They are at the bottom of the pecking list of course but not overly picked on. The hardest part about mixing them is not being able to feed them separately.

 

Wait as long as you can. When you do add them, be sure to check on them a lot. They can seem to be fine for a week then all of a sudden they begin to pick on them.
~Rebecca