Place chicken, carrots, bay leaves, onion and garlic head into a large pot. You don't need to peel onion, garlic or the carrots. You can use frozen chicken.
Fill the pot with water, bring the broth to a boil. Reduce heat to very low and leave it simmering for 3-4 hours.
Run through a drainer lined with a paper towel.
Don't discard chicken, break it into pieces and set aside, you can use it to make soup.
Store broth in a refrigerator for up to a week. You can also store broth in a freezer, using a plastic container, for several months. Don't freeze broth in glass jars, I have tried it and they break, as the broth freezes.