Two ideas leap to mind.
1. They are puppy training chickens so they could be called by puppy commands: Stay, Sit, Down, Drop, and Leave-it. I am already chuckling at the confusion this will create once Sherlock is fully trained and you are calling for the chickens to come for breakfast.
It is almost irresistible!
2. They are specifically Sherlock training chickens so they could be named after other fictional detectives. If you want all girl names you could have: (Miss) Marple, Nancy (Drew), Precious (Ramotswe), Jessica (Fletcher), and Jane (Rizzoli). Or if you aren't fussed about gender appropriateness you could mix in Monk, Columbo, Hercule or Poirot.