This is good advice!Less sunlight in the winter causes most hens to decrease or stop laying altogether for weeks or even months. Individuals will vary based on age and breed.
I think chickens handle cold better than heat. I don't do anything special for mine except to have places for them to keep out of the rain. If they are wet and we have a freeze overnight they might get some frostbite. Around here, a freeze and rain rarely come at the same time, so not usually a worry.
I do not winterize here since things do not freeze. Chickens will be fine in the rain as long as they have a place to stay dry at night.
I used to worry about them but they love the rain-- especially when the worms come up