Thank you very much for your reply.
I have found out in the worst ways possible' that the baby died suffocated inside the egg. Yes I heard some chirping but Rosie was always doing similar noises so I was very confused. I didn't number the eggs and so didn't know when exactly each egg was laid and I think this is were the problem was. I always thought the fertile egg was the last egg to hatch and so it would of been suppose to hatch on the 12th. This is a lesson I learnt in the thoughest way.
Rosie has abandon the eggs now and I have removed the nest box and put ozzy back together, they have been playing and helping each other on their second moult :) The good thing about all this is that I found out I have a boy and a girl for sure and that Rosie is a very strong bird! I have to thank you so much and I cannot believe that after so long Rosie is still a bird full of energy, and so much character, Ozzy is the male and unusual the best talker! He loves to repeat everything we say! I'm actually scared of saying something I should not near him as we could then start repeating...
Thanks to you and Keith I have two lovely birds, with great personalities and very strong babies. I felt guilty about what happen to the little baby but I guess it just wasn't meant to be. She is too young and I probably wasn't ready for the baby too. The baby was very healthy and had formed normal for what I saw in other baby conures, there was no pip marks which makes me very confused as he didn't even try to hatch...
Well, I shall now get my babies outside to enjoy this lovely weather, Rosie needs vitamin D to get her feathers colours vibrating again :) (inside the small cage :))
You have been amazing even after so long, thank you and Keith for everything,
Rafael, Ozzy and Rosie
Take care :)