Well, based on what my runners do, the mohawk and the open mouth are telling you that you make them very nervous for some reason.
 
It could be that they are trying to protect something or someone, or that they are anxious.
 
Things that can make them anxious include nutritional deficiencies (not enough of the right vitamins and minerals), changes in their environment, recent trauma and stress, not being used to being near you.
 
Poultry vitamins in their water, and quiet time near them gently tossing treats around yourself would address the first and last of those possibilities.
 
Look around and see if there is evidence of predators trying to get into their shelter at night.  That could put them in a BAD mood.