I live in a subdivision surrounded by woods and farmland.  We can hear the coyotes at night and have seen them a block away.  As a result, my ducks are locked in a covered pen from dusk to dawn.  During the day though, they free range in a 15 x 50 ft garden area until I get home and then they get the whole fenced yard (only because if they are out when I am not home they prefer my swimming pool).  I think the risk is worth it.  They are healthier getting to catch bugs, find worms, and eat dandelions and crabgrass they find in the lawn.  The predator I worry the most about is hawks which fly over frequently.  My neighbor put up two purple Martin houses this summer and I have seen those Martins chase off Cooper and Redtailed hawks.  Their squawking at danger also helps alert my birds to hide.  I say all this to say, yes, it is a gamble, but for the last year and a half all has gone well.  Give those babies some room to move and consider putting up some Martin houses.