Hello, i hav owned 2 budgies and 2 ringnecks before, yesterday i bought a new female budgie as my old one passed away, the new budgie has shown abnormal bhaviour ie: as soon as i put her into the cage, she seemed not at all afraid , she just started to munch on the corriander and went to the seeds, after abut 15 mins she was a bit fluffed, which i am confused about. She seems to be not affected by the environment change. My male was eager to meet her so i introduced him into the cage at first he did what she did and then sat beside her a bit away. What should i do/ is this some disease? currently she is sleeping whithout a worry with her head tucked on her back. And should i keep them seperate for now?