using System;

public class Program

{

    void Breakfast(){

        var bird = new Animal<Egg>();

        var pig = new Animal<Piglet>();

    }

    public static void Main()

    {

    }

    public class Animal<T> where T : Offspring{

        public T Offspring {get; set;}

    }

    public abstract class Offspring{

    }

    public class Egg : Offspring{

    }

    public class Piglet : Offspring{

    }

}