Man, I am really reaching back but if someone else can confirm, I think the term is "Pig Trick"??? I'll do some research.
On Edit: I thought I heard this on a Rangers broadcast in the eighties. Please take it for what it's worth. I don't think that people expect pigs to be thrown on the ice.
I remember hearing the term 'pig trick' as well. I think I read it one of those books that answers questions like, "Why do clocks run clockwise?" I think the question was, "Why are three goals called a hat-trick?" and I think they also threw in the concept of a pig trick as well.
I used the Google but couldn't find the term on any of the internets.