Welcome to Permies, Teresa Bell
1. How many hens?
2. How many square feet (approximately) per bird in your daytime area?
3. Do you have a way to introduce Roo slowly - meet and greet with fencing in between for a few days?
4. Do you feel you have a strongly dominant top hen? If so, she'd be the one to try to get to decide that Roo is an OK addition to *her* flock. If the hens 'henpeck' him too much, he may never learn to be a "kindly dominant" Roo.
5. What do you know about this roo? Was he raised by a real mom - incubator raised with a gaggle of birds all the same age with no adult
chickens to model civilized behavior can be a deal breaker, particularly if the Roo in question was either the only male or the biggest male. I've been given birds like that and had to cull them. A "civilized" Roo will court the women - uncivilized will force themselves on them. Hens don't like that behavior any more than humans do! However, even if incubator raised, if the Roo has a nice temperament, he may do just fine. I don't judge strictly on history, but give them the chance to show that they can figure it out.
6. Are you prepared to have to cull the boy, or can you give him back to wherever he came from, if you can't integrate him, or if he turns out to be a nasty troublemaker?
There is not guarantee with this sort of thing. I recently introduced a young, but more like 7 mnths, rooster to a group of about 14 hens that are over 2 years old and had never met a rooster before and they're all getting along fine.
I then introduced a second one to a group of just 2 girls, but they live with Noisy Ducks, including a drake, and the rooster was a little freaked out at first! However, he's figured it out and no one got hurt in the process.
However, my friend tried to introduce a young rooster to her flock of banties and one of the dominant hens ripped his butt area open and he never recovered. He was the nicest little guy, but the damage was done before my friend realized it.
There isn't a single
answer here. At some point, all you can do is try it but watch carefully for trouble and have a back-up plan!