The gene for naked necks (the officail name) is N and if the chicken carries two copies of that gene, the neck will bee completly naked or have a vsry small bow-tie on the neck. If only one gene is present the bow-tie will be larger. Since the three in your picture have small or no bow-tie, they have two N genes and are considered pure for naked so when bred together all offspring will be naked necks. If a NN is bred to a non naked neck 50% will be naked necks with large bow-tie, 25% with small bow-tie and 25% with feather necks. Those with feathers do not "carry" the naked neck gene because it is a dominate gene and will only be obvious as with offsprings with some degree of nakedness. Naked neck breed also have less feathers throught their body and are hardy, good foragers and mostly quiet birds. Your chipmunk bird may have one parent with feather and another with naked neck gene that was not inherited by offspring because with that breeding as stated above will not result in 100% naked necks. I am writing this here because a lot of us like to add different traits to our NN and need to understand that not all offspring will be what we are are wanting. Naked neck birds are a very good dual purpose breed that are fun to cross breed because you will know which offsprings are Naked and not wonder if a trait is being carried. You see what you get.