newly hatched chick

[bajabean]

We had a hen laying on 14 eggs. Today she starting walking around with two chicks but there is a third chick still in the nest that looks at though it just hatched, i.e. it's still wet. Should we do anything for the chick or will the hen go back to it? My only concern is that the hens have their nests in laying boxes. If we placed a heat lamp over the remaining eggs would that be enough to hatch out any chicks? We have another hen that is laying on 7 eggs but hasn't started hatching any yet. Would she accept the chick that is left from the other hen?

Thanks