You should not be seeing much of a drop in production in Utah. One of the blessing of the west is light. They will react to by climate conditions, such as drinking less because water is cold or using too much energy because their pen is drafty, or if over heated, but it is a form of stress.
Here in northern Arkansas, I\'m at peak egg production now with no additional lighting. August is my slow month, THE HEAT, and it drops to about 1/2 to 1/3. All in all, it is less than normal for no more than 2 mo.s But of course I breed for the egg ...