There are many elaborate recommendations regarding the best way to bring birds into mating condition. Some recommendations include placing them in separate cages, and setting up a very detailed schedule for adjusting the lights differently for the males and females. Others are as simple as putting them in a divided cage until they show signs of mating behavior, which will happen in the Spring when the daylight hours increase. Read a variety of recommendations and then get to know your birds and adapt to what works the best for you. You get to determine if you will use artificial lights and "push" the breeding, or if you will stay with daylight hours and follow nature more closely.
In general, there will be no mating until the number of day light hours reaches 12- 12 1/2. We use that as the primary method of conditioning birds for mating. This is followed by offering variety in their diet, and conditioning foods like Pentamine and an increased amount of green vegetables. Like with humans, some birds have a strong attraction for certain birds, and dislike for others within their same species. If they like each other they will mate immediately. An interesting experience in our aviary was last year when I had males in one flight cage and females in another that could not see each other. The lights had just been increased dramatically over a period of 2 weeks (which was faster than recommended but the birds had been signaling they were ready even though they were in winter hours). I noticed a particular male singing and a certain female responding with a chirp. They could not see each other. I was not ready to breed them yet (but the birds were) so I took a double breeder cage and decided to put them on each side of the partition so they could get to know each other and eventually, some weeks later, they would mate. The birds had another idea because I placed the male in, then the female, and was getting the partition (yes I did it in reverse order), when they mated. It took less than 10 minutes from the time they saw each other! Both were first timers, since they were less than a year old. I had to hurry up and give them a nest and nesting material and get ready for babies ahead of what my own time table had prescribed. The hen went on to lay 6 eggs and during the 2006 season they had 3 rounds of chicks with nearly 100% hatches. It was hard for me to turn her off from laying as Summer approached.
On the other hand, with another breeding pair, the hen lived with the male for several weeks until one day she accepted him and built her nest. She only wanted to breed twice in a season. She has done this for 3 straight years. Other hens, do not accept a particular male no matter what. Get to know your birds and adjust accordingly. Give them privacy and have a double cage with a divider in case they fight. Then you can let the male court her through the divider and you will see signs that let you judge when the time is right to remove the divider. Some signs of readiness include a male that feeds her through the bars, and a female that assumes the mating position when the male sings, tears paper, and carries nesting material. Most often, when the lights reach their point and trigger the hormones necessary for mating behavior, place the female in the male's cage and let nature take its course, but watch out for extreme fighting (not just little squabbles) and separate for a time if this happens.
Nesting (our nursery)
We use 4" open straw nests. You can see examples of this from the pictures. We typically support the nest by either having it rest on a metal holder, or by tying it to the top of the cage with a hook and string through the middle front, while securing the hooks on the back, through the bars of the cage. Those nests can tip and we do not like to have eggs crashing to the cage floor when the birds get too fussy or careless. Nesting material can be purchased or created from pieces of burlap bag, strings cut to less than 2", paper towel and newspaper shreds, and cotton pieces. Many times we use soft moss sold in craft stores. Place the nest in the cage and let the birds work on the nest. If by the time they start laying eggs the nest is a mess, or if they cannot build a good one, help them along a bit.
Some books recommend removing eggs as they are being laid and replacing with fake eggs until the bird is done laying, then returning the real eggs when the hen starts to incubate. We do not follow this method, in general. We find that the hens will start sitting on the eggs without interruption around the 3rd egg, and most eggs seem to hatch pretty close together. If eggs are removed, they must have air circulation and be turned a few times per day. It is easy to forget or damage them accidentally. We make individual exceptions if the hen continually destroys the nest in order to rebuild and tends to bury the eggs underneath the nest. We then replace them temporarily until they have perfected the nest and settled down.