There are four collie breeds and they can be quite different so you need to specify which collie you mean.

I have Border collies and they have quite a high prey drive. If they are introduced to other creatures from being pups, they are generally ok but, if not, they will chase and even kill and eat other creatures. Many dogs are ok with the cats that live with them but are not with strange cats and this can also apply to borders.
If it's an adult dog you are getting rather than a pup, then you can't guarantee it won't go for other creatures without getting plenty of info on it's general temperament and how it has been with other creatures previously.

Even with the strong herding instinct, a border can still attack sheep, ducks and other livestock if not trained. Herding is basically a modified type of hunting that lacks the attack and varying levels of training are often needed to stop a border from actually biting or attacking whatever it is herding.