I have 3 girls (RIR and EE) who were hatched in late March 2006, so they're now 2 1/4 years old. They molted this winter and began laying again in late January. Up until recently, I was getting 14 - 17 eggs a week from the three of them, typically 5 - 6 a week from the RIRs and 4 - 5 a week from the EE. On June 12 I purchased new bag of feed, the same brand and variety they've been using for the past year and a half. For the two 1/2 weeks afterwards, their egg production was about the same, then started dropping off. During the third week, egg production dropped and one RIR started laying soft shelled eggs. This isn't entirely unusual for her when she's starting to molt or coming out of one. She'll typically lay 2 soft shelled eggs, then stop laying, then begin a molt a week or two later. However, she laid 3 soft shelled eggs, then didn't lay (or ate the evidence!) for the next 8 days. Since then, she's laid 4 more soft eggs. Other than 2 lost feathers, she doesn't appear to be molting. The EE hasn't laid an egg for the past 5 days. Her last eggs had intact shells, but more brittle than normal. The other RIR has been laying eggs normally, but her shells are also thinner than usual. They have oyster shell available free choice at all times and it is being consumed. All of their combs are still red. What the heck is going on?