You don't say how old they are?
Any change, in flock mates, housing, feeding, lighting or watering will affect laying. They are not laying machines, they are sensate beings. They will lay when they feel happy, secure and that all is well with their world. Changes to any animate being are worrying and will affect them.
Do you have an vermin problems? Have you examined them for lice round their vents. Are red mite in the houses (though it should be the wrong time of year for that) Do foxes call round and get close to them when roosting? or prowl close by in the day? do you have rats? Not only will they eat the eggs they disturb the hens at night.
Have you lost any birds unexpectedly? Have they gone off their legs or displayed drooping wings? Are any sneezing or showing signs of discharge round their nostrils.
There is so much to learn as a poultry keeper, but it is a rewarding hobby/business. It just takes time and dedication
You say you have extra lighting. I take it the food and water is available to them all the time the lighting is on. It is not the hours of daylight which affect egg production, it is the amount of food they can consume within the hours they are awake. Obviously mash takes far more time and energy to actually eat than pellets.