So a week ago when my girls were just over 17 weeks, I put out oyster shell for the first time while I was finishing up my bag of grower feed. My 8 ladies gobbled up over 4 cups in 2 days. After that I have been leaving the container of shells outside the run so they have access while free ranging, but they are going ham over it again today! Could they really just need it that bad at 18.5 weeks? Or do they like it too much? Should I worry? Oh, and no one is laying yet.