Typically Guineas can start getting aggressive with each other or towards other poultry once they've matured enough for their hormones kick in... which can be anywhere from 8 wks old on up. Since it's late in the year/season you may not see any aggression from your Guineas until next Spring when the hormones flair again, and since your Guineas were hatched and raised by an Orpington Hen they may always respect your chickens, it really depends on the individual birds and the flock's dynamics tho. I would encourage as much free range time as possible, especially at the start of next Spring. Guineas in flocks that are confined to small areas usually experience aggression/territorial issues a lot sooner and to a worse degree than flocks that get plenty of free range time. Even tho your Guineas can fly out if they want to... I'd still open the pen and make them go out for free range time each day (weather permitting). Plenty of free range time/exercise has always been key to keeping the peace in my flocks... they are able to burn off their extra energy and aggression, and there's more room for the birds lower in the pecking order to get out of the way of any aggressors.Our guineas were hatched July 4th by an orpington hen. They are still following her around in a flock dynamic 10+ weeks later. Those that do fly out of the fencing ( 6 ft) go around constantly trying to get back in. When they free range, the guinea flock pretty much stays together with mama orp. Not all of the guineas will fly out-- only those that happen to roost outside a particular nite. They don't seem to want to leave mama inside the fence.
At what age shoudl we expect to see some bossiness start with the chickens? We have 12 guineas and about 20 hens and 2 roos. Chicken flock is marans, orps and EEs.