'Octomom' Nadya Suleman's 8 Kids Celebrate 14th Birthday with Vegan Donuts

Against what many considered all odds, Nadya Suleman, aka Octomom, and her octuplets are celebrating their 14th birthday ... and they are happy, healthy and thriving!

Check out the photo and video we got of Noah, Maliyah, Isaiah, Nariyah, Jonah, Makai, Josiah and Jeremiah all singing happy birthday before diving into some vegan donuts in honor of their big day.  BTW ... all 8 are vegans.

The 8 kiddos -- who are all vegan -- will celebrate the big 1-4 Thursday, but clearly, celebrations have already kicked off ... and there are 8 big smiles to mark the occasion.

It was way back in 2009 when Nadya was artificially inseminated in a BIG way. Doctors told her delivering 8 babies would be too much to handle, but Nadya was insistent.

Of course, there were doubters and haters ... many didn't believe she'd have the time or resources to handle 14 kids -- she had 6 of her own before the octuplets -- but she's made it work!!!