new chickens

It's difficult to advise when you don't know the age of your hens and you didn't mention  the breed. Most breeds do stop laying in the winter although everyone can tell you of exceptions. Hybrids are likely to lay thro the winter.

At the end of the day they lay when they are ready and there is a possibility it will not be until next Spring.

Re insulation - this is not usually necessary but again depends on the breed and also how many chooks you have as they get heat from each other.