I use girls' names, and associate them with concepts, like "Rebecca" is an old-fashioned name, sounds fairly North Eastern, like Plymouth. "Lacey" is associated with Silver Laced Wyandotte.
My rooster was supposed to be a pullet, and I named her "Carly" in memory of my sister who died recently. When Carly started to crow, I dropped the "y" and he became Carl.
Lots of folks use flower or plant names (Violet, Pansy, Rose, etc.).
I have a brand new chick which is itsy-bitsy compared to the others I bought the same day, so I thought of her as "Bitsy" and, in keeping with old fashioned girl names, I am calling her "Betsy."
Hope these samples help.