Hi Rose,
You need to remove all but the pair and the chicks. The pair is likely to attack the other birds, and the other birds are likely to attack the pair or kill the chicks. You should never have nest boxes or nests in a cage with more than one pair of birds. If they lay eggs anyway, the eggs can be discarded. If you want to breed, you have to separate the birds by pairs. Since you know nothing about these particular birds, some could be related, so I would not let them breed again. You also need to find homes for the chicks if they survive, or the parents or other birds will try to breed with them.
Thank you for asking Lafeber,
Brenda