You can feed a guinea pig “Timothy hay”, and they can receive large amounts of this, and you also feed them a bowl of pellets once a day. You can also include fresh fruits and vegetables as part of their diet.
A hamster only requires a small amount of pellets or seed mix once per day. Be careful not to overfeed your hamster as they like to store food in their cheeks and hide it in their cage for later. You can give your hamster treats such as fruits or vegetables that are safe for them to eat or commercial treats.