From the passage identify the sacred animals of Hera. Display the results in a comma separated format.

Context: Hera 

Queen of the gods, and goddess of women, marriage, childbirth, heirs, kings, and empires. She is the goddess of the sky, the wife and sister of Zeus, and the daughter of Cronus and Rhea. She was usually depicted as a regal woman in the prime of her life, wearing a diadem and veil and holding a lotus-tipped staff. Although she is the goddess of marriage, Zeus's many infidelities drive her to jealousy and vengefulness. Her sacred animals include the heifer, the peacock, and the cuckoo. Her Roman counterpart is Juno.

Answer: heifer, the peacock, the cuckoo