The so called Boosted Breeding has for me only worked during two weekend events when it was free, and i was speeding den up then too....well, it has worked once during ordinary playing too (or maybe it was a coincidence) but the times it has given nothing but junk dragons is numerous - so, i cannot see that adding boosted breeding to this 2nd den would make it worth it at all, but i do envy you who apparently has had better results!