Its a funny joke?

A chap was sitting in the pub with his dog next to a open log fire. A man walks up to him and says "nice dog,dose he do anything?" Ho yes" said the chap with the dog ,"he's an iornmonger!" "an iornmonger?" said the man.... "I just dont believe it !""do you want me to prove it to you?" said the chap..."yes"said the man !!so the chap got a red- hot poker from the fire, pushed it up the dogs backside... and the dog made a bolt for the door!!! was that funny? and by the way its from a birthday card.