The only difference between the growing formula, and the laying formula, is the protein/carb/fat ratios.
Something I like to do in the fall, when it's starting to cool off, is to use the leftover oil from the deep fryer that I save the rest of the year, and fry the feed in it until it's all used up. The extra fat helps them put on some weight for the winter. Plus it keeps me from having to let all that oil go to waste (waste not, want not).
As far as laying goes... if you ever eat shrimp for dinner, and have to peel the shells off the shrimp, give those shrimp shells to the chickens. The eggs are like, 1000 times better for a few weeks after they eat a shrimp dinner.