We have 4 chickens all the same age, 33 weeks. 2 Buffs, a Barred Rock and a Dominique. The Barred Rock, Dominique and 1 Buff all started laying around 21 weeks. The other Buff is our biggest chicken, she grew the fastest and we thought she would lay first. But she hasn't laid any eggs, and has hardly any comb and wattle. We've found 2 rubber eggs in the coop under the roost bar this week, and suspect her. We offer free choice oyster shells for calcium, organic layer feed, plenty of fresh water and apple cider vinegar in one water pan. What else can we try? I can't figure out why she would be so old and not be laying! Thanks for any advice.