How long is a piece of string? As you say, it's normal. You are probably changing them to a different brand of feed as well so that may have a temporary effect. They have the stress of the move. So don't panic.
Are any of them looking scraggy or losing feathers? It's moulting time for hens and they won't lay during this time. Nothing to worry about, it's normal. It's also normal for commercial birds to be dispersed before moult as they don't want to feed them through it!
How much corn are you giving them? I believe the recommendation is a thimble full per bird late in the day and only in colder weather. Too much can make them fat quite quickly and stop them laying. A little bit before bed gives them a nice energy boost for bed time to keep them cozy.
Did you mention how old they are? Or what breed? Some rarer breeds will stop laying altogether in winter. Our Welsummers don't lay at all until spring. Keep in mind that all hens have pretty much the same number of eggs to give whether they lay them all in 2 years or spread them over 6-7.