Depending on the field, the ideal situation would be to strip graze it.  Move a poly wire each day for the amount they can eat in that day.  You are right, you will waste a lot if you turn them out on it all at once, but if your setup or available labor doesn't fit strip grazing, it is better than nothing and you will likely still get a lot of grazing days out of it.  If you haven't socked a lot of N to it you should be fine on nitrates, your only risk may be acidosis if you turn them out on it all at once, just fill them up on hay berore turnout and throw a round bale out there, likely won't see any problems at all, especially since it sounds like there are a lot of nubbin ears out there.