Our leghorn has been laying consistently for about a month, giving us nearly an egg per day. At first she was laying every other day or so, but then settled in and the eggs got big and very consistent. All of a sudden we haven't gotten an egg from her for about 4 days. Our ladies are free ranged, so l locked them up so they couldn't hide the eggs, but still nothing (and everyone else is still laying very regularly in the next boxes). She seems vigorous and perky otherwise, and although we had some REALLY hot days over a week ago, this week has been mild and pleasant... Ideas? Should I be concerned? Thanks!