Something really strange while birthing...

Question
We have a Jack Russell female.  She was bred to a Rat Terrier Male.  This is her first litter.  She had a pretty tough time during the whole birthing process.  She threw six puppies, all are in GREAT shape and nursing really well.  My question is this:  After her third puppy was born, she birthed the fourth one really quickly. This pup had it's own sack, but along with it was a smaller sack.  (Attached to it's backside.)  When this sack was punctured, (by the bitch), it contained this green, cloudy, jello-like substance and it had a really foul smell.  (Like rotten meat.)  The bitch proceeded to eat it, along with the fourth puppy's sack.  She immediately vomited, and the green was SO dark that it actually 'dyed' the third puppy, and her legs.  This green was like Easter egg dye!!  The foul smell continued until after all of the puppies were born, and mama went outside for her potty break.  After she came in, we tried to wash her up a bit, using NO shampoo or chemicals.  Is it possible that this could have been an undeveloped puppy?  I have NEVER seen this during whelping.  Especially this bold color of green.  Any information you can give me will be greatly appreciated.  Everything is fine, other than that, and I guess I just need to know if by her eating that, will it effect her in the next few days, especially since she is nursing the remaining healty pups.

Answer
Hi! I've seen this before. What it is is a puppy that died, and started to decompose inside of mom. It's lucky that it didn't make her go into labor earlier. If she vomited right after eating it, then she'll probably be fine. Just keep a good eye on her and her temp for a few days to make sure she didn't get an infection. One of my girls gave birth to something like this before. As soon as it came out, she went straight to eating it before I could get it from her. She too vomited, but was perfectly fine afterwards. Like I said, she should be fine. Just watch out for a high temp, and make sure she's eating and drinking. Also, keep an eye out on her milk, color, and such. Good luck!