How to get our Havanese not to eat his poop?

Sounds silly but you are going to have to really stay on top of picking up his stool right after he goes. For some odd reason some dogs pick up this nasty habit, typically it is just that, a nasty habit. You can try adding meat tenderizer in his meals. The idea is that it make s the dogs stool taste really bad. Normally this helps but again like I mentioned above the number one way is to pick up his stool right away when possible. Best of Luck!

I think your first step is to discuss this with your vet and to eliminate any other issue that may be present, sometimes a change in food helps. Best of luck