Any issue with having a female mallard duck along with light, medium and heavy breeds along with 2 female mini-sebastopols? Currently have 20 ducks of all different sizes and breeds but a female mallard should be 1-2 lbs lighter than my smallest ducks. Only 1 male Ancona and everyone else is a female. Free ranged in mornings and evenings and in a 25' x 125' covered pen during the day and Tuff Shed coop at night. Thanks for any input.