Hi,
It is very responsible of you to be doing your research before you set them up for breeding. Too many people do not do anything until they see an egg, or even worse, newly hatched chicks. As you are learning, there is a lot you need to do when breeding birds, before you give them the nest box.
I would not plan to give them a nest box for at least 6 more months. They may be capable of breeding at this age, but they are not mature enough to settle down and be good breeders. Captive raised birds become sexually mature at a much younger age than in the wild, but they really are not ready to breed and they tend to make mistakes or develop bad habits.
If you do decide to breed them when they are old enough, you will have to wait and see if seeing each other seems to be a problem. Sometimes visible barriers are necessary, although parakeets generally will be fine as long as the other pair can’t access their cage. Being across the room should be fine. Once you do give both pairs a nest box, then you will need to stop letting them out of the cage during breeding season. They need a lot of privacy when they are breeding, so that they do not feel that the chicks are threatened. In captivity, these birds will try to breed year round, so you must remove the nest box when the chicks are weaned and make the parents rest. During this time, they can be let out again. They should be limited to two clutches per year, with about a 6 month rest between clutches. Any chicks need to be given away or placed in different cages. You do not want any related birds to breed – the chicks will breed with the parents or each other when they are old enough if you do not separate them.
For now, make sure the birds are on a nutritionally balanced diet – loose seed will not provide adequate nutrition. They need pellets or one of our foraging diets. Our Nutri-Berries, Avi-Cakes and Pellet-Berries are nutritionally balanced the same as a pellet, but they are not ground up. They contain fresh, whole hulled seeds with other nutritious ingredients. They can be fed alone or along with pellets. In addition, you can offer dark leafy greens, chopped veggies, fruits, and multi grain bread. When they are old enough to breed and have their nest box, you can also start feeding them cooked eggs with the shells crushed and cooked with them. Wash the eggshell thoroughly before you break the eggs. The eggs and shell provide the extra protein and calcium that th female needs. You can also make sure she has a cuttlebone.
Thank you for asking Lafeber,
Brenda