I'm a dog walker and we have many dogs come to board with us whilst their owners go on holiday...we regularly have a golden retriever stay and he just cannot resist eating the chicken droppings. He's never gone home poorly and despite me alerting the owners, we've never had an issue in 3 years. It's disgusting (rabbit droppings and horse muck are also a particular favourite) but seems harmless. Fear not, as previously mentioned in another post...at least they're not eating your chucks.