So today I noticed something strange on my 3 year old female mallard. She has a medium sized bulge under her mouth. Its soft. Its not in her moth, or in her throat (?). Earlier this week I had my flock tested by the State for Avian influenza, and they all tested negative. Does anyone have any ideas what this might be? She isn't acting any different, and there are no other notable health problems. I currently have her quarantined from the rest of the flock. Thanks!