I've seen some dogs that wouldn't make a single attempt to bark at a pig in a pen, but when you let it out they get going like they knew what to do the whole time. I think some dogs just feel too closed in in a pen and are more worried about how to get out than they are about the pig. The worst thing you can do is let a pig hit a dog in a pen that is already scared of a pen. If you do, good luck getting them back in there. Sure bay contest are fun and exciting to watch, but if you think about it, most of these dogs were bred to work out in the pasture everyday of their lives. If you want a pen dog, go get a chihuahua or a dachshund. I guarentee you they'll bark in a pen