I started with Pekins and Mallards. Mine all free-range. I now have a nighthouse. Many nights, the Mallards do not care to be closed up. They can fly over the fenced backyard to avoid predators.
I am amazed that my Mallards hang with my non-flying ducks right around the house. I live on a farm with about 23 acres of water. They sometimes graze close to the water's edge, buy all my ducks confine themselves to the kiddie pool rather than enter the pond since my Pekin, P!nk, was taken by a snapping turtle.
My Mallards do love the kiddie pool much more than the Pekins and Runners. They also leave the rest of the flock sometimes (in pairs) and go out of sight.
They lay the most perfect green eggs! YUM!