Set back in paper training

Question
I have two 19 week old yorkie-poo puppies.  We decided to use training pads with the intention of moving them outside in the spring.  They took to it very well and after having them for about 4 weeks, they were both very good at always hitting the spot when they needed to go.  We use one training pad in our kitchen next to the door we will eventually use to let them outside. Now, one of them has decided that he never wants to pee on the pad.  He still will poop on the pad, but very rarely pee.  He still pees in the kitchen, just in the middle of the floor.  He will do this right in front of us also.

Can you tell me if there is anything we can do to change this behavior? We have tried overly praising him when he does rarely go on the pad and stopping him and saying "NO" firmly when he goes on the floor, but he has continued to do this for a couple weeks now and I've run out of ideas. They both did so well when we were initially training them, but I don't know why one of them has chosen to stop.

Answer
That sounds a little young to be challenging your leadership, but could be.  The key to most behavior problems is approaching things using the dog's natural instincts. Dogs see all the people and dogs in the household as a pack with each having their own rank in the pack and a top dog. Life is much easier if the 2 legged pack members outrank the 4 legged ones. You can learn to play the role of top dog by reading some books or going to a good obedience class. A good obedience class or book is about you being top dog, not about rewarding standard commands with a treat. Start at http://www.dogsbestfriend.com/ For more on being top dog, see http://www.dogbreedinfo.com./topdogrules.htm

You might try adding a second pad.  I think dogs want to go near where they went before, but in a slightly different spot.