Combine chicken, carrots, onions, tomatoes, water, sea salt and pepper in a saucepan.
Put bones and bay leaf in a strainer that will fit your saucepan and place the strainer in the saucepan, making sure the bones are mostly covered with the liquid. You might need to redistribute the vegetables so that it does.
Heat to a boil, then cover and reduce heat to low. Simmer covered for 45 minutes to an hour.
Remove the strainer with the bones and bay leaf and discard.