Most cats will actually be scared of a chicken due to its size, but the two animals will soon realise that neither poses a threat to one another. Dogs can be a little more of a risk to your chickens because they’re bigger. However, you will know your dog well enough to be able to judge its temperament and how it would react to chickens. The important thing is that your dog is not aggressive towards the chickens, they must learn that the chickens are part of the family too.