Most of our layers and roosters have names, we have about 25 or 30 right now... but they usually are due to some behavior or physical characteristic and the names were given over a long period of time....in reality it makes it easier for DH and I to discuss things which need done with individuals.... it has been handy to be able to identify which broody we are talking about when something happens such as egg additions or removals and chicks hatched or lost. We don't name any of the chicks which are destined for sale or freezer, though we do identify them by broody and breed/sex. A number of our hens weren't named until they went broody... we use colored zip ties to tell them apart, so often it was 'red/left' or 'green/right' and the names came later. Our roosters actually respond to their names! LOL .... so they know who is getting yelled at!
We don't name the meat birds at all, but usually refer to them as the sumos... and further differentiate based on size... mini, small, medium or big guy/girl....again it is done to facilitate phone conversations about health issues or activities, behaviors. (since I am gone for 24 hours at a time a few times a week)