Of course it's better if there are also vegetables and table scraps for the chickens to eat in addition to corn - a good idea might be to research old feed recipes.
My comment about dogs was aimed at those who get a dog and envision it as a guard dog without taking the time and effort to TRAIN the dog. I've seen a number of these "guard" (actually, pet) dogs ruin their owners' or their owners' neighbors efforts at chicken-keeping.
Having a guard dog isn't only a matter of breed - plenty of mutts can do the job just fine, if their owner spends the TIME and EFFORT to TRAIN them correctly. That's the hard part.