He's just adjusting to his new environment. Please dont try to hold him/pester him. Try lightly singing to him a couple days from now, I know they love that. You cannot integrate the budgie until a couple of months later. A few ways to ensure that they wont fight is a month from now you can put...
I'm getting some 4 week old silkies soon to put in a separate flock with out other silkie, Baby. We're only getting 3 of them and I need some advice. Baby is a very kind and skittish chicken and I want her to be happy.
Have you tried to mount him? You grab him back the feathers on the back of his neck and hold him against the ground. Do this everyday for a week and hopefully he should realize you're the leader. If not, you might just have to cull him/get rid of him
You might have to cull him, but if that's not an option for you, you can try to mount him. You just pin him to the ground for around a minute and continue everyday for about a week. I dont know how well it works, but it tamed one of my aggressive roos.