Anyone ever seen this before, almost looks like he pooped out his intestine, still acting normal otherwise……
Could you get a closer picture of the vent area without his tail feathers blocking it? It's difficult to tell what his problem is. Here is a picture of a prolapsed vent and a link about them, in case that is the problem: http://www.the-chicken-chick.com/2012/04/prolapse-vent-causes-treatment-graphic.html
Good news, with these negative New England temps it ended up being a giant frozen accumulation of poop frozen to the feathers around his vent
That's kind of what I was thinking it was. It's great that it was not anything serious. You might want to trim feathers around the vent to prevent a buildup of droppings. It tends to happen if they have diarrhea, and then it can cake up.