I wouldn't use corn as a staple of their diet. It's delicious, and they love it, but it's like potato chips for humans. Junk food. Just carbs and sugar.
This is my (future) method:
My birds eat chick starter (18% protein) and will for their entire lives. Once my birds get to laying age, I will have a container of oyster shells for them so they can take as much extra calcium as they need. They know how much to eat.
The calcium in layer pellets isn't enough sometimes, and once they're too old to lay the extra calcium built into the layer feed can actually cause kidney damage and kill them. It's also harmful to birds too young to lay, and any boy chickens that will never lay. Basically, layer feed is ONLY appropriate for hens of laying age. It's bad for everyone else. Not sure if you have a mixed flock or not, but something to consider.
Bottom Line: Get them whatever feed you want at the moment since they're supposed to be laying, and offer oyster shell free choice on the side. Cut out the corn entirely and see if they start laying. If you want to start giving them a little corn as a treat once they've started laying again you can, but don't make it a major part of their diet.
Hope this helps
And may I say again how flippin' cute they are? I just want to cuddle them
