How do you stop the neighbors with dogs from leaving stools around my house?

Start with a sign in front of your house saying that clean up after the dogs is required. It's technically both littering and trespass to allow your dog to crap in someone else's yard. If you know who it belongs to, then clean it up, put it in a bag, and take it to the person's house with a note saying they forgot this, and you are returning it. Allowing your dog (or cat for that matter) to crap on someone else's property and not clean it up is both lazy and rude

Where I live in the UK, the local Environmental Health will DNA test the poop and the dogs, then fine them a huge amount per pile, plus costs.

I wouldnt tackle them directly, they know its wrong and they're likely to retaliate.

Make a compliant to the city saying that dogs owners dont clean up after their dogs .. that is considered as littering in public or other private properties areas

I have put up notices out front asking people to PICK UP after their dogs, but this only resulted in somebody picking it up an chucking it (the notice). If being there when this happens doesn't work, you may have to call your local environmental health authorities or fence off your front. Bushes with prickles work in terms of keeping dogs off.

Have a professional clean the feces up and send the bill to neighbor with a detail statement as to why his is getting the bill.

Report them to animal control.

If you know who they are, return the feces to their front doorstep. I've had to do that at two places I've lived, and it worked.

you get a shovel and put it around their house

I usually deposit it in their mailbox. It's worked so far.