So, My cockatiel is 10 months old and this is my first one so I do not really know their demeaner that much. We have the baby but also adopted a cockatiel that is around 20 years of age, he is pretty mean. if you get near him, he will start to try an bite you. We recently let the nice one start hanging out with the mean cockatiel, does this mean the young one will start to be mean as well? I don’t want her to pick up the older ones bad habits.
I’m not too experienced with elder cockatiels; my oldest was 5 when he was rehomed to us (he’s now 6-7). He was very bonded to his previous owner and eventually bonded to us, but at first he was very aggressive with hands. We actually taught him to be less aggressive by example of our younger cockatiel Rosie who’s very sweet and knows how to get scratches and step up. I found that Rosie would pick up on his aggression at times when he would peck at her feet and try to bite her when he didn’t want to play. After a while she would reciprocate the aggression and it was getting to where I wasn’t sure if they could be housed together, so they were ultimately separated into different cages and only allowed to play together on neutral ground (like a play stand or the kitchen table).
I found that showing our older bird Oscar how I interacted with Rosie while he was in his cage helped him to become less aggressive with hands and me in general. As for aggression towards each other, I would be very careful and make sure that they are supervised 100% so nobody gets hurt. It’s definitely possible that the younger one can pick up on the aggression; I would just give them time to adjust to one another in neutral territory sharing food and toys together if possible. Sorry for the long response!