Cage sizes for cockatiels

Question
What is a good size cage for three/four breeder cockatiels...they will not be let out of the cage for play time, thanks.

Answer
First off if they are breeders they should be housed sepratley to keep from fighting over nest sights and mates. you could either have one cage about 24inches square and then an aviary to let all the birds out int when they aren't breeding. Or I would reccomend a space about 3 feet square if they are going to be in it for all the time. To be honest it really bothers me that you say they will not be let out of the cage for play time birds NEED the stimulation so I would house them in as large a space possible by a window or outside where they will have constant stimulation. Also you say 3 or 4 you should always have an even number to pair up otherwise they may fight or pick on the odd bird. I'm not trying to sound mean this is just my opinion and I wish you the best of luck in your breeding endeavour!