Most dragons will successfully breed, but the more important question is will it be healthy to let the dragons breed. If you are questioning if they are too old, Im curious as to how old these dragons are? Why not buy a baby or two, raise them and learn more about them, and then when they are ready to breed................go for it and let them breed? Then you would know what kind of shape they are in, or how old they are, and have a good foundation for babies. This will also give you time to see them go through all the growing steps and get into breeding with a good amount of knowledge. Do you have any dragons now? Or had any experience with them? Just probing for a little more background. Chris