You know you don't need to do that right? Once you have two of the same dragons, you breed them together and they will give you the same dragon! So, if you put smoke and smoke together, they will breed a smoke dragon.
That's how a lot of players breed. I wait until I have 2 of the same dragon and then I put them breeding together and I get my third egg. Rather than have a third dragon of the same type, I don't hatch that egg. Instead, I place it on a egg pedestal for display.
There are some dragons I have more than two of because they earn big $. For me I have 6 Olympus habitats and they all hold gold Olympus dragons. Overnight they earn lots of money, more than one rainbow.
Hope that helps

diz diz dizzy