Need help with a nesting situation

[Love My Perch]

Hi all, we have four parakeets in a decent sized cage (as well as and Amazon, Meyers and a cockatiel). Yesterday I had a major incident with the keet’s, Tiki, Blue Bean, Green Bean (all female’s) amd Pastel who’s the male. I know I’m doing something wrong so I’m here for advice. I heard a very loud fight happening and ran over to find Tiki on top of Green and apparently winning (Tiki on top). I was able to break it up and Green got out of there and flew down the hall. Then Tiki took after Blue and another battle erupted, this time Tiki drew blood. My wife and I teamed up and finally caught her and removed her to another cage. I’m the past few weeks, Tiki has laid two clutches of about 6 eggs. Blue also laid the same and oddly they both cared for them in the same nesting box (all infertile btw). This time Howe was Grean Brans turn and Tiki wouldn’t have. Threw out of the box and clobbered her. I neglected to mention we have one (I know, first mistake?). Tiki WAS finger trained before we added the others slowly.
Also, I pitched all the eggs (infertile). Maybe should pull out the box altogether?
Can anyone offer some suggestions and also what I’m doing wrong (to prevent this again)? I’m sure I’m missing some vital information. Thanks! (Tiki is the pretty whit and Pastel is next to her, very pretty mutation)