Welcome to YT! I have 2 little Yorkie girls and have fostered Yorkies for rescues. Most the rescue dogs eat the feces - I've heard so many suggestions as to why they do but the simple fact is we humans find it totally disgusting!
Some of the rescues I finally broke of eating their feces but only by completely housebreaking them. I take them outside to potty on a leash and when they do poop get them away from it immediately. I never say NO or even draw attention to it just lead them away. Once I take them back inside I go out and clean up. It took some time but once they realize it isnt necessary for them to "get rid" of their own feces they quit eating it.
I tried some of the spray on remedies but they never worked for me.
Best of luck!
And YES mill babies need good parents too! They didnt ask to be born into such horrible conditions - but it is up to all of us to be diligent about researching where our pups come from and help close down those nasty places by writing our congressmen/women.