I have three chickens, and up until this fall, I've been getting three eggs per day. They are only a year old so I don't think it's from age. I now only get one egg every other day. They used to eat the eggs for a while, but i always saw shells and there are no shells in the boxes. What would cause this. I also have a daylight bulb on a timer to extend light hours. Please help me get my chickens laying again!