Male Budgie Fighting With Other Males Over Female

[Diamond 0]

Hello! This is my first post here but here is my question...

I have 6 budgies: 3 males and 3 females. One male and one female seem fairly bonded, they spend all their time together, preen each other and just appear to be very lovey towards each other. Houdini (male) and Doddie (female) We have had them for 2 months or so now and within the last week and a half we have started to notice some, for lack of a better word, aggressive behavior from Houdini. 

Now Doddie has clipped wings from the breeder that supplied the pet store so she can't fly, so she climbs about the cage and gets out and walks on top of it. But if Houdini is outside the cage and Doddie is inside sitting with another male he will sit right above them and make a ruckus and look straight down and flap his wings over them. That is where it started...and now in the last few days when they are all inside the cage (which is massive By The Way) Houdini will chase after the other two males at times. Which we have only witnessed it about 3 times in 2 days when we are home from work. 

Should I be concerned? Before all this they all seemed to be getting along exceptionally well, and outside of Houdini chasing the others at times, they seem to still get along fairly well. Is there anything I can do to curb the aggression? (if that is what it is)

I do want to add, whenever one of us is home we open the cage and they have the ability to choose to go in and out and fly around and have some "free time" for hours on end. They all do fly around (besides the two females that came pre clipped) and even if they can't fly they still crawl around to the perches and toys we have on the outside and even walk around on top. 

[JackRussel 0]

Intraspecific Struggle. Don't worry, what will be - will be.