I think part of your intent was to identify other myths. Some of these may be more misconceptions that myths, but I think they are in the same vein. I know, I picked some easy ones.
A rooster will kill any chicks that are not his own.
Two roosters will fight to the death. Three will not.
Pointed eggs make roosters. Rounded eggs make hens.
With a rooster/hen ratio of 1/10, you will never get any barebacked hens.
Fertile eggs are more nutritious than unfertile eggs.
You cannot eat fertile eggs.
You can store unfertile eggs longer than fertile eggs.
Medicated feed contains antibiotics. (Some might, but most contain amprolium which is not an antibiotic.)
Editted to add: Another use for golf balls is to move a broody hen and make sure she stays broody before you give her the real eggs you want to hatch.