I have 18 hens just over a year old. I get between 13 and 18 eggs a day, have been for many months. However for the last week I have been getting 1 egg white with no yolk and no shell. The next day it's 1 yolk no shell no white. Back and fourth. The get an all flock grower with oyster shell on the side. I have narrowed it down to 1 of 5 girls as I have 3 breeds all laying different shades of egg. What causes this strange egg factory mistake? Can I help her or do I just keep her happy and fed until she passes?