Zebra finches laid eggs?

my zebra finches have laid eggs and have been sitting on them for 7 days now i gave them a cuttle bone and they have been eating it and drops to put in their food with alot of protein i change their water every two days their cage is 3 feet wide and 2 feet high i gave them nesting material and they laid the eggs and are sitting on them they are always happy and healthy i have a boy and a girl and they mated and laid there eggs and are sitting on them for 7 days thank you