Supplementing Layer Hens

Hi everyone!
I've been using this website for quite some time now since I got my very first flock of chicks ever this last fall. My girls have started laying approx. 2 weeks ago and I'm up to about 5 hens laying now. I feed them layer feed and cracked corn and a oats with molasses here and there, maybe even a mea lworm treat. I know that laying an egg and the whole process for them is supposed to take from them, so I guess my question is really is there any chicken supplements or vitamins that they should be taking in addition to their layer feed? Should they get anything additional to replace anything lost that I'm not already giving them? I've got all Orpington hens-- Lavender, Buff, Australorps & Blue Orpingtons! I noticed they've been going through a lot of cracked corn more than their layer feed (maybe because of the cold weather?) I just want to make sure I'm doing everything possible to keep my girls happy and healthy!

Thanks so much!!