[header] How to choose between a shelter or a breeder dog [title] Decide if you want a puppy or an adult dog. [step] One of the big differences between shelter and breeders is the age of the dog when you take him home. While shelters do have puppies, born to pregnant dogs that were abandoned, by far the majority of the dogs they have are adults. 
However, the reverse is true for breeders. They are in the business of selling puppies, and their adult dogs are rarely for sale as they are either pets or breeding stock.