Maybe your chicks don't identify as humans? that may be your problem right there, Joe. by calling them boys and girls, you're forcing them into a human identity. Your signs need to say pullets and cockerels.....assuming your chicks identify as chickens
.That could open up a whole thing right there....maybe one identifies as a duck? So you need signs saying drake and hen (is there another name for immature male and female ducks?) I think, to cover all your bases and not offend any of your chicks, you need signs that list all possible names for both male and female of all the species your birds could possibly identify as. So they'll feel comfortable, you know.
And, not to be Anglo-centric, but you're printing the signs in English. maybe your chicks aren't English speakers. You need to have the signs in multiple languages, or offer a translator.