Ducks laying fertile eggs

[Welshies]

Thank you sooo much. the field is huge by our standards as a 600 acre organic welsh sheep hill farm. its maybe 15 acres. though i've heard in the US and Canada you have much more land usually.we are a small farm compared to those around us though. we let them out between 6-7 usually and occasionally 8-ish, so probably no chance of them nesting out side.
cheers for the replies!

Ah yes, we have a lot more land here in Canada! Good luck with your ducks.