I've never added light, but that said, the biggest thing in keeping my egg production up through winter is to get new layers every year. I tend to cull out birds at the start of their 2nd or maybe 3rd winter if they are in the layer flock. (Just before their major adult moult) Right now I am greatly downsized due to out of state school, but I have 5 leghorns from this spring that are still giving me 4-5 eggs per day. I am still getting about 2.5 dozen per week and will cull them next fall and have them replaced with another 5 in the spring. They started laying in July.
47 birds is A LOT of birds to feed with no return. But of course, if they are pets, they are pets and food cost doesn't matter.