Hi Pam,
I would not put him with a flock yet. He is likely to get badly bullied given his age and temperament. Are you sure this is a male? How old are the birds in the flock and how many are there? Cockatiels can live fairly peacefully in a flock if the cage is large enough, you never give them nests, and you have an even number of birds. Generally you need a large walk-in type aviary. Cockatiels are very territorial when they are breeding, so you should never try breeding them in a flock or give them anything they can use as a nest. With any species, it is never a good idea to have an odd number of birds. In most cases they pair off, regardless of gender, and the odd bird gets bullied and chased. You should also never out male and female cockatiels together until they are at least 2 years old. This is the minimum breeding age. They can breed at a younger age, but they still have some physical and mental development to go through. If a young hen is caged with older males, she is likely to try to lay eggs when she isn’t old enough, and this can result in egg binding, which can be fatal. If you put a young male with older cockatiels, they are likely to bully him and the females may even attack him. They may show interest in him as a mate, and if he isn’t receptive, they may get aggressive and hurt him.
Thank you for asking Lafeber,
Brenda