The two chicks are an accident of recessive genes. Their eggs were the result of the mating of a hen and a rooster from another very rare, closely-related, almost-extinct breed–Black Java chickens.

A pair of auburn Java chicks hatched at the Kohl Children’s Museum on April 6 and 8, and Chicago Parent stopped by to bask in their fame. Rusty and Lucy (named for Lucille Ball) spent themorning ...