Disgusting as it is for us, provided the 'donor' dog is healthy there is nothing to actually harm the dog eating it. Pineapple in the dog's food can help, but getting a dog to eat pineapple can be a problem. Best thing is to take away the 'trophy' element i.e. if you rush out to pick it up the dog thinks it is worth having and will race you for it. Try distraction, either shaking a can with stones in, or a favourite treat or biscuit calling the dog away and making it sit so that leaving the poo is more rewarding. Throwing a toy can also work, or else resort to taking it out on a lead till both dogs have been, and then you can let her off as a reward once you have cleared up.