behavior

I have a buck that has been doing something that I have never seen or heard of before, and I was wondering if anyone can shed some light on this behavior. What he does is take a deep breath then slowly pushes the air out his semi closed nostrils, making a sound like some one letting the air out...

I'm not sure what to think about this. Last evening my partner went into one of our pens to tag 2 fawns that were born a few hours earlier. He went in and found one but before he could do anything the mom went completely bonkers. She came charging down on him, barking like a dog he said, but...