what has prompted a couple of my girls (i have 4) to start laying their eggs not in their nesting boxes but in their poop box? other than being inconvenient and sometimes messy, it's not a big deal but i'd like them to use their boxes. their roosts are highest point, poop box below, 2 nest boxes on separate wall half-way up the wall, they've been fine for 2 years laying in boxes till last month. thanks to jodyjo for responding...i will try curtains on the boxes. any other suggestions?