You know, I've seen a few cockfights in person, and everytime they put these spikes on the rooster's legs so they can claw each other to death. Now, I'm no expert at this, but it seemed the cockfight in the Seinfeld episode didn't include spikes. They focussed on "pecking"...which is just a small part of a REAL cockfight. Now, don't know if this is how it's done in NY, or if the writers have never seen one, but I think they made a teeeeeny little error there.
BUT!!!! The episode was a funny one. :)