I have 3 hens ( White leghorn, Barred Rock, and Buff Orphington). They are approx. 5 mos old. The Rock and Orphington have been laying consistently large nice eggs for several weeks. The Leghorn has laid 2 eggs, but small. She has layed several eggs that have poorly formed shells and she lays them outside the nesting box. She also seems to be outcast and the other 2 have formed a "click", but not being aggresive towards her or preventing her from getting food. Any ideas?