I would guess it depends on your females, and the size of the cage. We had two females and added two males, which went really well, but I don't think I'd have had four females together. Our two bickered a lot, but that's actually reduced now we've got the boys. Our cage is 36" x 19" x 40" which is about the minimum four two budgies, and they do use the whole space. Ours also all need their own space away from each other to sleep in, away from the other three. We kept the males caged next to the females for a couple of weeks while they were getting introduced. They had time out the cage together and all got along together. Then the males got to visit in the females cage in the evenings before bedtime. And finally when we decided the were ok together, the cage was rearranged totally, and the males moved in. I find the males mellow out our cage a lot. But really it depends on the temperament of the females.