Well IMO if a cat is bred over several days by different toms (or even one tom) you could have "older" kittens conceived. Cats are induced ovalators which means they release eggs when bred. If a cat is still in heat over a period of days some kittens could be born premature and not survive.
Most breeders only allow the tom and queen to mate how ever many times they want in a 1 or 2 day period for good conception. Then she is taken away from him.
But, would the first conceived kittens necessarily be the first born? How does that work? Couldn't they get all jumbled in utero? (I do not mean this to sound confrontational, at all! It's really just something I've wondered)
I don't really know - just assuming, but in the case of Olive's litter and the fact that kittens are opening eyes a lot sooner then they should, something has to be mixed up. Maybe the first eggs implant in the lower part.
I assumed that the first implantations occur "lower" in the uterus. One reason I assumed that is that in Smudge's (the Ragdoll) litter, the mom went into labor on April 4, and had a stillborn, almost hairless very small kitten. Then stopped labor until 2 days later, on April 6, and had 5 more. They were not premature looking, but they were a "bit" small. So I was thinking that the later conceived kitten was more toward the "outside."
My Sasha was Born Aug 24th with her Brother. Two days later more were born but died a few days later. I will ask my Brother how many were born the same day as Sasha. My Sasha will be 2 in Aug but is a small Cat and thin Cat. I got her when she was 3 Months.
Its a good paper project, but how you would tell where they got implanted and when, would be something next to impossible without killing the mom or babies!
I have heard that cats can have one litter from two different fathers!
I thought this might have been the case with the litter that Dave had come from as there are two local tom cats, one big and black and the other was a stripy white/grey colour.
When the litter came out there were 3 pure black boys and all the girls had a lot of white and grey in them.
Do people believe this is true and do you think this was what happened?
I'm not sure about date of implantation, but with many other mammals, inutero position in terms of gender makes a difference. Here's an article concerning this topic... very interesting, and would also make a fascinating senior paper!
Any animals that are not in a controlled breeding program can and do mate with more then one male. Its very possible that EACH kitten can have a different father if a group of toms bred a female in a short amount of time