Don't over fed treats. The won't get a "complete" diet if you do which will lead to problems down the road.Yes. They get layer pellets. The warm oatmeal is a nice warmup to start the day in this cold weather. The scratch is also to warm them up and give them something to do when stuck in the coop. .
Scratch doesn't keep them any warmer than their complete feed does.

Glad you joined.
I will agree that 80g is a massive size egg. Do you have older hens? Generally, Red Sex Links and Rhode Island reds eggs size will increase rapidly once they begin approaching 2 years of age. This often leads to egg bound problems or problems with the oviduct.