Whether birds are breeding or not, it is generally not a good idea to have an odd number of birds in one cage. The odd bird eventually becomes left out and is often attacked and bullied by the others. For breeding, you definitely should only have one pair of birds in the cage. It sounds like the male and younger female have bonded, so you need to remove the older hen to a separate cage and possibly another room. If the pair were to lay eggs with her in the same cage, she is very likely to raid the nest and destroy the eggs. Another scenario is the breeding pair may start to attack her, and territorial cockatiels can be vicious. They can easily kill the extra female in minutes if they decide she is a threat. In the wild, another bird like this would be viewed as a rival or intruder and would be driven away with attacks. In a cage, the female would have no escape and they would end up killing her. I cannot warn you sternly enough to remove this extra hen before something bad happens – they may seem like one big happy family now, but it will not last.
As for the breeding, it is important that your birds are on a nutritionally balanced diet like pellets or our foraging diets. A loose seed mix is not adequate for breeding or pet birds. In addition, the breeding pair needs fresh foods – chopped veggies and fruits – multi grain bread and cooked eggs. Wash the egg shell first, break it up in with the egg and cook it all together. Breeding birds will eat a lot of extra foods once they lay eggs and especially if chicks hatch and need to be fed. Once they are feeding chicks, you will need to add more foods throughout the day. You need to give them privacy from the other female. Even being in another cage, if they can see her they still may be upset and may not settle down and lay eggs. You also need to be prepared to hand feed chicks if they hatch any but aren’t feeding them. You will need baby bird formula and something to use as a brooder to keep them warm. You should have these supplies on hand before your birds hatch chicks. And if they do successfully raise chicks, you need to have a cage to put the chicks in after they are weaned – they can NOT remain with the parents. And you need to be able to find homes for them. Related birds should not be allowed to breed, so if you keep them, you can’t keep males and females together and you can’t let them be with the parents because the parents will either keep trying to drive them away, or will end up breeding with them when they are old enough.
Once the extra female is removed, you may still have along wait before the hen lays eggs. She may or may not. It sounds like the male is more ready for breeding than the female is right now. Not all birds make good breeders, so eggs do not mean chicks, and hatched chicks do not always survive. You need a lot of patience to breed birds and you need to be prepared for failures, as most parent birds make mistakes with the first clutch or so. You also need to plan to remove the nest box and rest your parent birds for several months between clutches. In the wild they would usually only have one clutch per year because breeding season is limited. We provide a perfect breeding environment with indoor birds, so we have to force them to rest and ideally limit the pair to only 2 clutches per year.
Thank you for asking Lafeber,