Hi Stanley,
I am not an expert

on pigeon racing/keeping but I will give you a brief description of what I do with my young birds and hopefully you might be able to use some of this information with your young birds, good luck.
I have 2 sections for young birds, one section is for the 1st round and the other is for the 2nd & 3rd rounds. I loft fly them separate until the pigeons in both sections are loft flying for almost the same amount of time ( about 30-45 minutes ) and then I release both sections at the same time.
I usually wait until my young birds are about 2 months old before I let them out for the first time, but I would not recommend that to a new fancier entering the sport as it is nerve wrecking to watch because the birds are usually all over the place for the 1st couple of days and most of the time I lose 1-2 pigeons or more as they are too strong on the wing, to be on the safe side it is best to start letting them out at 25-30 days old.
After they been out for a couple of weeks I start showing them that they have wings and that they can use them to fly

, I use a swimming pool net to remove them from the landing board (slowly as to not scared them that they don`t want to come back to loft again) several times until they start to fly for 20 minutes or more, then when I am ready to have them ranging I watch them closely for about 10-14 days, and I remove any pigeons from the team that are injured or are coming back to the loft too earlier when they should still be flying, because those pigeons keep bringing the other pigeons down and in my opinion they never become good pigeons anyways, so I just remove them from the team.
Many people say that their pigeons don`t range because they are on the dark or that they let them out too late in the afternoon ,etc, etc, what I have learned about getting pigeons to range is that they have to be around the same age and you have to remove the injured pigeons and the trouble makers from the team ( the ones that come down when they should still be flying) to get your pigeons to range, but thats easier said then done with most people as most people are not willing to remove pigeons from the team because of who the parents are or how much money they paid for them, etc, etc.
I have seen people ship pigeons that were smashed up so bad that I would not even have that bird in my loft, and their answer was that, oh this pigeon is from so and so , or it`s only a broken leg, etc, etc, I never see an injured athlete win a major competition, unless it is a competition for special athletes.
I start training my young birds most of the time 2-3 weeks before their races start because I am concentrating more on the old bird and their races, but you can start training your young birds at anytime that you feel comfortable that they are ready to start their road training.
There are many differente ways of doing things, all you have to do is find a way that works for you, a very important thing that you have to watch is their health, you can have the best pigeons in the world, but if they are not healty you will never accomplish much in the races, and a very important rule about young birds is that you should always keep your young birds a little hungry, like that it is easier for you to control them as they will listen to you much better.
Paul Tavares;