When to integrate 2. Week old chicks with 7 week old chicks?

[hginochio]

Awesome!! I know I am about a year late on this thread but am happy I found it. I am trying to do the same thing right now. I bought 5 hens from the same farm. 3 older girls (ranging from 8-11 weeks) and 2 younger girls (a little over 4 weeks I think). I want to put the together as soon as possible because I dont want to have to deal with a hard integration. I put the 2 smaller girls (silkies) in with the bigger girls (delaware, australorp, and orphington) today in the run. I watched them pretty closely and I think they did pretty well. The delware is the bossiest of them all and was the only one pecking and charging occasionally at the silkies. Once the silkies got away from her pecking, she went on with her business as usual. She didn't really chase them around the run. Sooo, tonight, I want to add the silkies in with the bigger girls and see how it goes. I am wondering if I have to put a heat lamp in for the smaller girls, but I dont want to fry my older ones either. I am just so nervous because I dont want to wake up with any injured or deceased chickens. If anyone has any tips, or encouraging words, I am all ears