I have nigies and big goats....
I have heard what MEME has too. Honestly it always puzzles me.
Of all the Nigie owners and breeders I know I know of two that has had kidding troubles. One, was because the buck used was not a true Nigie but was huge and produced 7 lb kids... the buck of that person is now in my freezer. The Second one- Is a breeder that waits til 2 years, and she has had kidding problems.
None of my goats have had a problem and successfully nurse triplets with no intervention.
Nigies tend to mature, IMO, much faster than the larger goats. Doelings have already gone into their first heat BY 12 weeks, the bucklings need be seperated early.. no later than 8 weeks, they can reproduce. They wean sooner, mine at 6wks are fully weaned... that doesn't mean they won't nibble but they can go to their new homes at 6-8 wks... I wait the 8wks. Our larger goats wean at 90 or more days. The Nigies tend to get to their desired size earlier also. I have had one fully ready at 9-10 months, others at 12-15 months. My Lamancha needed to wait to get her size right. Nigies are also year round breeders as opposed to seasonal breeders. I am sure this has something to do with it. Most Nigies bounce back very quickly. Probably because their kids are tiny and they can get back into "shape" easier. I have never had a nigie lose condition after birthing either, but of course internally I know they still need time to recuperate.
It may be just a "fluke" but the people I know that have Nigies have the least amount of parasite issues too. Of course stock, management etc has alot to do with that.