Cracked corn is crap like chips of the chicken world. Tasty but lacking in nutrients including protein, amino acids, vitamins and minerals that are added into our formulated rations.... which are often made from mostly corn already.
Yes, it's true that diminished nutrition can cause a whole host of issues including decreased laying, and immunity to parasites and disease. Adding in the corn can even contribute to fatty liver syndrome and possibly failure or death... though *most* likely in birds that genetically predisposed somehow, such as Orpington.
With regards to "layer" mash... I never use "layer" feed partly because it only has 16% protein which is about the bare minimum for light bodied layers like Leghorn. Dual purpose birds such as Rocks or Marans will do best with not less then 18%. But also because I don't want my roosters, broody's, molter's, or juveniles to have the added calcium of "layer" which *can* (doesn't mean will) cause kidney issues including gout and even failure... again, *most* likely in birds that have been genetically predisposed. I keep my birds for breeding so nutrition is important to me. 22% protein was shown to give the best hatch rates, which to me says more nutrition in the eggs my family is consuming. Also feathers are made from 90% protein and it's amino acids.
Your birds will actually get the most nutrition if you use a formulated ration such as layer, grower, flock raiser, or even starter. The main differences in ALL the feeds is going to be protein and calcium content. But YES... it sounds like that person DID give you accurate information regarding corn verses layer feed.
My preference... is (Purina) Flock raiser with 20% protein, and oyster shell available free choice on the SIDE for active layers to take what they need. While non layers may sample the OS, they are able to avoid it and not likely to overdose, which in juveniles can stunt growth and delay onset of lay.
The general rule of thumb to keep things balanced as mentioned by the other poster is... not more than 10% of their total daily intake in treats.
Hey, hope you are enjoying BYC!
Good for you for looking into the nutrition thing. It's ALWAYS a good idea to get a second or even third opinion on this type of stuff since plenty of folks are well meaning but sadly often misinformed.
