I think the running away and acting like you're killing them when you do catch them and pick them up is a male thing for sure. I have four, ten week old goslings, two females and two ganders. They were nest hatched this year and I removed them on day one and have been their sole caretaker. The females are delightful and let me pick them up when I need to without any fuss, but the males are doing exactly as you describe. My adult gander was friendly really up until he turned two with me but now he will randomly decide to attack me and for sure any stranger he encounters. Nobody and I mean nobody can come in our back yard now unless I get him penned up because I can't trust him not to attack.