Honestly it looks like a coturnix quail egg, so it should take about 18 days to hatch. I can't believe you have them wandering in your yard! Someone must have released it, as they are not native any place in this country. You could actually try to catch the adults as well, I doubt there are any regulations against it, not on those birds anyway.
If it is a coturnix, she probably did just drop it. Most coturnix don't set their eggs, it has been bred out of them. So most likely the only way that egg would hatch is if something else set on it (like your incubator
). But I would try to catch the adults too
If it is a coturnix, she probably did just drop it. Most coturnix don't set their eggs, it has been bred out of them. So most likely the only way that egg would hatch is if something else set on it (like your incubator

