Don't know why dogs do this, but many do it as puppies. Some NEVER stop doing it. It's a good reason for you to pick up poops as soon as possible. Oh---be warned--If your little one likes doggie poops, he'll LOVE cat poops.
There are products you can buy (including meat tenderizer) to put in a dog's food so the end result is not so appealing. These have met with mixed success, according to several YT members.