Your fence spacing.. do you have coons? there could be a reach and grab... ask me how i know this?
I hear (from this forum) hardware cloth for the bottom 2-3ft to keep a predator like a coon from reaching in. My ducks are out in a dog run daily.. i only have chicken wire and privacy lattice to down the size of my chain link for now(i had nothing before and a duck suffered an attack).. it's way better than it was but my ducks are removed now at night ... i will be hardware clothing(lol) the bottom as time and finances allow..