Update:
I've already written a bit in my generic fids thread but basically recently we were moving out and the Bourkes were under my parents' care for nearly 3 months. Recently I returned for a longer time and I am sadly disappointed by what Rozalka did during my absence

Yesterday I noticed that Jaś wing feathers are somehow destroyed. Later I noticed a few feathers on the cage bottom like they were pulled off... and then I heard Jaś screaming because Rozalka attacked him. Today he screamed again and it was pretty loud because I was on another floor and I heard him well. Of course it was Rozalka again.
I ended up punishing Rozalka by seperating her to another cage. I didn't want to do it to her but I felt bad for Jaś. I wouldn't be surprised if he can't even fly anymore becau
e of her because one of his wings has just two primary feathers left, including one is already broken.
Sometimes I wonder if Rozalka hates Jaś because of the past - originally I had only her and Fela until I got Jaś who "took over" Fela and became her partner

But I honestly don't know why she is like that.