My cocktiels! I had a cocktiel and a Budgie that use to be in the same cage, but my budgie died and since my?

cocktiel was really depressed so we got him two more cocktiels. We got him a male and female that were caged together. Well my old cocktiel would occasionally hit the male, who's a little younger. The younger male is so innocent he never hits my other older cocktiel. Now my female cocktiel just laid eggs and the female and older cocktiel have been beating the crap out of my younger male cocktiel! It's so sad! My poor little male cocktiel. We had to take him out of the cage. The older male and female are being so mean to him! And my younger cocktiel is really attached to them. What should I do???!