I know that this question has been posted before but as a novice I have an additional question that I could not find the answer to so just thought I'd start the topic over again. We have a flock of 4, one leghorn, a rir, a wyandotte and an orpington. They were all born on Memorial day this year. Our RIR is the only one of our four that has been laying. She started right before halloween and seemed to follow the usual pattern of an egg every couple of days. Then last week no eggs and I noticed some 'goo' sticking to her tail feathers. The following day I was in the run and noticed she was acting odd (slow gait and squatting positions) and I saw her lay an egg w/no shell. I read on this site that this is normal and suggestions for it. I had been feeding them laying feed, some scratch and our leftover greens. I have stopped giving the scratch, went out and bought oyster shell supplement 4 days ago and have provided it in a separate feeder which all the girls are nibbling from. I have also started supplementing with extra light in their house. The shell-less eggs have persisted as of today. How many days does it take for this situation to correct itself? When should I worry. Also, should I worry that my other girls are not laying? TIA!