UV unwrap going bonkers

Hello one and all.

I am working on a model of a horse and while trying to unwrap the uv I ended up with a right mess for some reason. I’m attaching a screen shot so you can understand better my problem. This problem so far seems to only bother this model, although I haven’t tested on anything as high poly as this one is.
All I did was add some seams and then hit U and unwrap. The other forms of unwrapping still seem to work just fine, however I would like to use just the unwrap.

If anyone could tell me if it’s something I did that caused this or if this is an actual bug, it would be much appreciated. I am using the 2.76 version.

Attachments


You have vertices pinned (red dots) in the UV unwrap. Is that intentional ? If not unpin them.

Are the seams placed correctly
If you have double vertices remove them

Supply demo blend file so we can review