Neutering is the only way to prevent marking.
You need to be prepared for the reponses you will get after this thread. Many will not hold back on how they feel about not "fixing" your pups. Also, There are many passionate breeders who put a lot into it and get upset by people who just "try" for the fun of it without knowing anything about breeding.
Please don't get offended if mean things are said. I honestly think you shoud have your pups "fixed" though.
