I, personally, would not consume the eggs in the discovered nests.
Do you have an enclosed run that can be used to "home" the birds to your coop for a week or so? If so, simply keep them in the pen, bait the nests and let nature take it's course - since they will be unable to get out and visit the nests they have chosen they will start to look for nests in the coop and (hopefully) use the nest boxes. As birds of habit, they *should* continue to lay in the nest boxes for the most part once you start allowing them to range again, though some are just free spirits and will fight you every step of the way by getting sneakier and sneakier about nesting elsewhere. Unfortunately, right now, the habit they have formed is to lay elsewhere, so you are not just building the desired habit, but also unprogramming the unwanted one. If you are up to it, consider it a daily Easter Egg hunt on those days you find your count in the boxes to be suspect *or* you can confine them for most of the day and release them once most of the eggs you would expect for that day have been laid.