Used to feed our chicken all kinds of table scaps but egg laying was inconsistent. Local farmer gave me some advice to keep laying chickens on a well balanced layer-feed mix with all the necessary ingredients and my hens are very consistent now. Used to feel good recycling scraps to the...
2.5 yrs old isn't too old. I had some that were 6 years old that finally quit. Make sure you're giving them the 14 plus daylight hours with a light set up compensate the shorter days.
Have my light come on 4:30am so that they will get sufficient light. Shuts off at 8:00am. Cold has not affected their laying. In fact my 3 of my young hens have just started laying in the midst of the cold stretch here in the Northeast. 9 eggs today 12 hens.