I actually have had no predator problems, but I do have 2 chocolate labs that have free range of our back yard (Dont kill birds) and they do help protect them from anything that might wander in.
Here are my Muscovy Breeder pens.I currently have 8 of these for trios, but have a 25' by 50' area where I keep my geese and extra Muscovies. Also have some chain link pens as Muscovy breeder pens.
Right Side
Aisle Way (Drain down to middle to drain water pans)