siblings

I have two Cockatiels that come from the same breeder, and they both seem fight a bit. I'm curious if this would be normal behavior? I know it's normal for siblings to bicker once in a while but i want to know if it's the same with cockatiels.

Hi Everyone, This is my first post on here, it's so good to have a community I can ask about my beautiful birds. I recently got two babies (Lily and Daisy, 7 weeks old - they are now ~12-13 weeks old), they are brother and sister and were inseparable from the beginning, I was initially going...