Dogs hunt with ears, eyes, and finally nose. Maybe not the dumb young pups early in the season, but if they survive and grow up, they learn this lesson well. They will confirm with their nose what they are hearing and seeing, which is why they almost always approach from down wind. We can never eliminate our scent, but do everything you can to lesson it. Don't wash your clothes in laundry detergents, you can make great "scent free" laundry soaps out of baking soda and ivory soap. Many youtube videos are available on this. Don't have your nice clean coat hanging up in the kitchen and fry bacon for breakfast, you can smell it for days. If you can smell your buddy, or he can smell you, the dogs will smell you miles away.