Genetics questions!

Okay, I have read and read and read about genetics, but it is just not sticking! I'm used to horse genetics which I'm pretty good at, but I think they might be easier than mouse genetics!

Anyway, I have started breeding a little. Color is sort of secondary to me right now--mostly I just want to improve type, temperament and health because I'm working with pet store mice. My goal is to get a nice large healthy pet-type mouse with a good personality that is easy to handle. I wasn't originally going to breed but I was so dissatisfied with the availability of good pet-type mice that I decided to just do it myself. If I can get down to one or two colors that's great, but I'm starting with kind of a large variety!

Anyway, I have a pink-eyed satin recessive yellow doe that I bred to a blue fox buck. Kind of a weird pairing I guess but I was going after the mother's temperment (she is so sweet!) and the father's type (he's jumpy but very handsome). She had a huge litter that she culled down to seven. I thought about culling further but they've all got full bellies and she seems very unstressed, so I'm just gonna roll with it.

I was expecting some crappy reds I could possibly breed back and work from there.
Instead I got...brindle!?? 5 brindle babies and two that look red.

Isn't brindle dominant? They appear to be Avy--it looks like black or blue striping on a red base, and the males have the coloration too so it's not sex linked.
Is it possible the mother was brindled but doesn't show it?

The mom was likely brindle, either undermarked or with stripes too light to see! Of course, you did not get to see the whole litter, but if the whole litter was brindle, then mom is Avy/Avy. With a blue father, you should have at least gotten a few black mice, unless mom was homozygous for brindle.

Yup..... I completely agree. lol