I have around 60 adult chickens at the moment and hardly anyone is laying eggs.... My main flock (egg layers only) have started laying again but not to their full extent. My wyandottes have barely given me eggs all summer and fall! I knew the heat was a huge factor with the summer because it was getting in the 100's but now it is cooling off and still barely anything! All of them are healthy, parasite free, have very large pens to roam in, clean feed, etc. Could they be lacking a vitamin? Is their a kind of food I can give them to boost production? Also all the hens are a 1-1.5 years except for 2 hens which are pushing 3.5-4 years. Whats surprising is the old hens lay more than the young ones! The young ones are "new" additions compared to the 3 years old but they have been here for a year now; 4 others for 3+ months. Any ideas what could be causing them not to lay as much?