Hi, I noticed today that one of my budgie’s vent has become stained green because of feces, and every couple of seconds he’ll open his mouth. I originally thought he was adjusting his crop but he’s not closing his eyes or stretching his neck, he’s also been doing it for a long time. I did switch to a new food the other week but he’s only just started showing signs so I don’t think it’s that. Can some people please give me some ideas of what it could be? I’ve already contacted the regular vet and asked if anyone specialises in birds and I’m waiting for a reply. Apart from the mouth opening and dirty vent, he is acting normally.