stray puppy peeing inside

Question
One week ago while hiking I found an approx. 6 month old lab/border collie mix puppy. He took surprisingly well to my home, dogs, and routine. But 5 days after having him here he began to pee on my carpet. Once with me standing in the room, the other times when I was not. He didn't even have an accident on a day when I couldn't make it home for lunch and he was locked up for 9 hours. My other two dogs, and the adult lab I found with him, do not urinate indoors. The only theory I have is marking territory, but he's neutered and still squats. I'm going to foster him till the local rescue agency can find him a home, so I'd like to get him trained as best I can so he gets a great home. Thanks!

Answer
When you are around you need to keep a close eye on the dog. Use closed doors or gates to keep it in the same room as you are, and perhaps as I do, a short chain fastened to the computer desk. If you catch it in the act, give it a sharp ''Ah, ah, ah!'' and take it out. When you can't watch it, crate it.

Other dogs may not be as bad as the young Labs I am plagued with. Still your house and dog will be much safer with the dog in a crate when you are away. The dog may be happier in its den than loose in the house. It relaxes, it feels safe in its den. It rests, the body slows down reducing the need for water and relieving its self. Dogs that have been crated all along do very well. Many of them will rest in their crates even when the door is open. I think the plastic ones give the dog more of a safe, enclosed den feeling. They are harder for dogs to open too. Metal ones can be put in a corner or covered with something the dog can't pull in and chew. Select a crate just big enough for the full grown dog to stretch out in.

Leave it some toys. Perhaps a Kong filled with peanut butter. Don't leave anything in the crate the dog might chew up. It will do fine without even any bedding. You will come home to a safe dog and a house you can enjoy.

A dog that has not been crated since it was little, make take some work. Start out just putting its toys and treats in the crate. Praise it for going in. If you have been able to trust it with any bedding, put that in the crate. Feed it in the crate. This is also an easy way to maintain order at feeding time for more than one dog.

If it is marking, he needs obedience training.  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