can i introduce new chicken?

[szy.cpr]

i have 5 3 month old chicks ,they are quite big and have been out side for a while, i want to get 2 RIR, can i just put them in with the other chickens or will this cause problems, oh the RIR will be grown chickens

 

[FamilyOfChickens]

You need to quarantine the new birds for at least a month before putting them in with the flock.
https://www.backyardchickens.com/forum/viewtopic.php?id=12751

Once you've done that and no problems have showed up, the new ones should have some sort of enclosure in with the 3 month olds so that they can get used to each other without being able to kill each other.

Good luck.