Muscovy tends to be dark and rich while other breeds can be lighter or even more fatty. The other difference between breeds tends to be size. A Muscovy leg quarters is the size of a healthy chicken leg. So, if you can only get hold of a smaller breed, you may need to pull the duck out of the oven a little sooner.
And you’re probably asking yourself, “90 min??” Duck leg and duck breast doesn’t cook up quite the same as chicken. For duck leg, a lower temp and longer cooking time will yield better results.
131 is an ideal temp, slow sear until crisp.