I have two BAD puppies

So.. I have two BAD puppies. They are into everything, but mostly it is their continuous chewing of things. Papers, poops (yea that's right), shoes, everything. Well, Newell and I spent all of yesterday decorating the house. The house looks great. I get up this morning, let everyone out, and brought the puppies back into the house. Put the gate up and went to work out. When I got back, they had gone behind the Christmas tree and pulled out the extension cord and chewed that like it was a milk bone. I mean, into tiny pieces. Why in the world would they do that? And extension cord doesn't look like food, smell like food or taste like food. But there they were, their little innocent faces with pieces of the plastic hanging out of their mouths. Thank goodness the tree wasn't plugged in, we would have had bar b qued puppies.