Return all Generic List objects that implement an interface

Question

I'm attempting to return all Animal objects that implement IHerd.

Could someone point me in the direction?

public interface IHerd {
        void Herd();
    }

    public class Dog : Animals, IHerd {
        public void Herd() {
            // Swim method
        }
    }

    public class Animals {
        public void Eat() { }
        public void Poop() { }
    }

    public class Farm {
        public List<Animals> FarmAnimals = new List<Animals>();

        public Animals GetHerders() {
            return FarmAnimals.OfType<IHerd>();
        }
    }

Answer 1

return Animals.OfType<IHerd>().OfType<Animals>()