Frustrating second litter

My silver fox doe had her second litter last Thursday, 33 days after she was bred I had almost given up. She had seven, six right away and the seventh later in the day. The seventh was out in her run area and not in the nest box and was dead with some limbs missing (as in she ate them) then over the next three days, all but two died and looked like they were bloated but with formed fecal material. One of the two remaining ones needed to be euthanized as it's stomach was so bloated his side had a tear and there was blood on his bottom. It was awful. The remaining one is massive and doing extremely well.
Anyone have any thought about what went wrong here? She had six last time and one was lost right away but the other five did well until a cold snap at three weeks old caught two of them out of the nest box and they died. The three remaining of that litter are doing great.
Do you think my doe is a poor mother? I was thinking of maybe trying a different one.
Parasites, while not impossible, are unlikely as no one has shown any signs of parasitic infection and are kept in cages off the ground. I am a vet tech and have done exams on the parents and they look healthy and no visible signs of illness.

I would try a third breeding.

I definitly plan on it in a few days, that way the one remaining guy will be out befor the new ones move in.

I don't think she is a bad mom at all. The one was probably stuck and dead upon arrival and she tried to clean up the proof of babies.

Coccidiosis could be a cause. chickens can give it to them. It can also be transmitted from a parent who has it in their feces or it can develop on feces if they are exposed to oxygen and within reach after, I believe, 48 hours. I had impeccably clean cages and sanitized 2 times a week with each cleaning. I lost 10 babies that year to it out of nowhere. All it took was for one little poop not to go all the way through to transform what is natural behavior into something very bad. It could also just be the genetics between buck and doe crossing funny. Just a few options. Coccidiosis usually hits in some of the cleanest kept areas in my experience. Really is a nasty thing. (It can also lay dormant and they can be carriers of it and not show any signs). One thing my vet told me was that it is similar to pasturella, that nost every rabbit has some amount of it in their systems. It is a matter of keeping it at a level that the rabbit can handle it and that depends on the rabbits immune system.

Well, I am down to one kit left but he (or she, haven't checked that yet) is thriving! It is the biggest baby I have ever seen. It was easily double any of it's littermate and feels bigger than I remember any of the last litter being.
On another note, I went to check on everything yesterday afternoon and noticed the food bin had been left open and it was raining all day. I got back inside and said that something must have tried to get into the food bin but it has locking clamps so I wasn't sure what it could be. He was like, our daughter likes to play in the food, didn't you know this? Nope, not until right now. New thing to check every day.

Glad to hear that the one kit is doing well!

Bummer about the feed bin!