Yes, and you will occasionally. But if you have a good dog you haven't failed as bad. My dogs look after my ducks. The only time I've ever lost ducks was when I had the dog inside. The ducks steal the dogs' food and do other things they should get teeth for but these dogs being a herding mix will spook yet never actually attack the ducks. If the dogs wanted to they could kill every duck like they do stray cats and squirrels. They chase foreign birds like they're trying to kill them too, they're just not successful. This is normal dog behavior. Most dogs go their whole life only guarding and killing what they're supposed to. Kids can be more aggravating to a dog than a duck and you have to watch that of course. But in almost all cases the dog will protect the child like they would livestock and puppies. This is an asset. I've accidentally left a kid out of sight and when I returned the dog had taken up a position nearby, just watching. I've also observed my dogs pulling puppies back from the road, something I haven't been a poor enough parent yet to observe with a toddler.