I am new to chickens. I purchased my first chickens from a local farm. He had several chickens and I told him I wanted young layers. Four of the chickens I believe are Scott Greys and were said to be about 16 months old. Although I don't really know how to tell, they look old. I've had them for about 3 months and not 1 egg. I expected an adjustment period but not 3 months. Also, how old before most chickens start laying?