The filling in these chicken pies is made up of cooked chicken, so any leftover chicken or turkey will work, perhaps you have some leftover rotisserie chicken or turkey from Thanksgiving. Mixed with a variety of frozen vegetables of your choice, so peas, carrots, sweetcorn, or similar. Together, the vegetables and the chicken are cooked in a creamy chicken soup. The soup is a condensed soup, so it's thick, and not diluted. This gives you the thickness you need in the pies. If you were to use regular chicken soup, it would be way too watery and you'll end up with a soggy mess!