My rabbit just had One baby! Why?

 
My rabbit just had One baby! Why?
This is the 31st day of my rabbit being pregnant. At around 12:45am this afternoon, she gave birth to only 1 still born (dead) baby. I checked to see if there was anything "stuck" in the birth canal and saw nothing. Why would she give birth to only 1 baby? It looked like it was fully formed. Will she have more soon? Thanks so much for any help you can give. Oh, and please no rude sarcastic answers. Thanks!
If she hasn't had anything yet then she wont have anymore. It depends on her size. Smaller breeds will have less babies. Netherland Dwarfs and "The Minis" (mini rex, mini lop, etc) usually have about 1-4. Dutch, lop, and dwarfs are usually 4-6, Rex, Angoras, Californians, etc are about 4-8 and the giant breeds (Flemish Giant, Checkered Giant, New Zeland) are usually about 6-10+. Stillbirths are common in first-time moms and rabbits who are stressed. I'm really sorry to hear about your loss, but at least you wont have to find homes for alot of babies. Try not to let mom get pregnant again by getting her spayed. pets question and answers,www.5d2d.com

My rabbit had 8 babies back in May and it's hard caring for all of them especially when they grow up. I'd have been glad to have just one baby. Again sorry for you loss and I hope i helped you out.
I would check with a vet. It'd be very bad if there was one hidden inside of her and it's rotting. I'm sorry for your loss.
I think its generation.