My chickens don't even notice them anymore. They get to many treats lol. We have been free ranging them for awhile without issue. I need more room for my ducks though. We don't have a pond. My friend free ranges her ducks and they don't eat anything but she has 40 acres. They sleep on her porch and are around all her things. I can't decide if mine would be ok or not because we don't have near that much property...
We've free ranged ducks before and they did okay but their place of living was far from the house...I'd not want duck splats on the porches and such. WAY worse than chickens and that's bad enough.
Yours would probably be okay on a small property, as there is less chance for them to get too far from shelter in their foraging. My ducks were GREAT foragers and ranged as far as the chickens did when they were in open acreage, but not as far in this smaller meadow of 3 acres.