I have two hens that are laying odd eggs. These girls are both about 6 months old. One is a leghorn who keeps laying a membrane only egg always very early in the morning (unfortunately I can't figure out which one as I have 8 leghorns :/ and we are talking earlier than 6 am before sun-up), and a plymouth bar rock who keeps laying a very thin shelled egg with very little pigment and quite infrequently for her age/breed. The eggs are calcified, but feel rough like fine grit sandpaper and they break very easily. They are on a laying feed and have oyster shell free feed and are free ranged throughout the day and roosted in the coop at night. The other 11 hens all lay normal, thick shelled eggs. Everyone's crops and waddles are bright, healthy appearing red and otherwise bright, alert and happy. I do have two other leghorns with bumbble foot, but no other's showing signs. Is there something that can be addressed that I am just missing or do these hens need to be culled?