I had neighbors in the apartment complex who were dumping seed by the gallon onto the lawn; my vet didn't worry about the actual seed as much as about the bacteria in the bird droppings that birds leave when they feed. He said he has treated several dogs for giardia they got from eating bird poop when they scrounge for dropped seeds . (They were also leaving piles of sunflower seeds, bread and other human food out for the birds at the foot of my stairs and i needed both my doctor and my social worker to file complaints to get it stopped). Please don't endanger a dog because you like to watch birds -- move the feeder or stick to the tiny round seeds that don't seem to have much scent, unlike sunflower seeds.