I just integrated a 7 mo cockerel w my flock of 2 hens and 6 pullets who are a month older than he. Five of the pullets were immediately accepting of him, but because of the naysayers, and his shyness, I had to separate him in a partitioned part of the run and coop. After 3 weeks, and several trial meetings with one or more of the girls, it's all one big happy family now. So far, he is very polite to all the ladies and takes no for an answer. He's a bantam Cochin, the girls are various breeds/sizes.
I did not have the ability to truly quarantine him, so I relied on my questioning his former owner and just trusted it would be okay. I am not saying this is a good idea, but it's what I did. It's been a month, and so hopefully we are out of the woods. I guess we're never really out of the woods......
I got such good advice/counseling here on BYC 're this and other questions. I can't thank BYC community enough....