Hi,
First, you need to take away the sand sheet. They do not need grit, and if they do eat any, it remains in their system forever. It can eventually cause an impaction that they will die from. Hopefully they have only chewed it and not eaten the sand or grit. You can give them a cuttlebone and a mineral block, but make sure the mineral block is not the type that contains grit.
As for breeding, they must use the nest box or you need to stop trying to breed them. They do not like nesting material, so attach the nest box as high as possible to the outside of the cage, with no nesting material. If she lays eggs again, move the eggs there. If she did hatch eggs on the cage floor, the chicks usually die because she can’t keep them together or keep them warm enough.
Breeding birds need a nutritionally complete diet such as pellets – a seed diet does not provide any nutrition, only fat. Also offer leafy greens, chopped veggies and you can offer a daily egg food. Either a commercial dry egg food or cook an egg with the shell washed, crushed and cooked with the eggs. Only offer egg food when they are breeding. Do not leave the nest box up all year. If they do have eggs again, you must remove the box and rest the pair after the chicks leave it, or if the eggs fail to hatch.
At 2 years old, your birds are barely old enough for breeding. You should not breed cockatiels until they are 2-3 years old. The problem before was probably due to her being too young, and having the eggs on the cage floor. Also, not all birds are compatible as mates They may get along, but they may not have a mate bond. All you can do is provide what they need and give them plenty of privacy and hopefully they produce chicks.
Thank you for asking Lafeber,
Brenda
