Hello everyone! This is long, sorry!

I have been raising my own mice for a little while now in order to offer my smallest hatchlings until they get onto the size of rat my LFS carries in frozen.

In any event, this is my setup:
10 gal tank, 3 mice per tank (1 male, 2 females). They are given lab blocks and I throw in little treats like chew logs, almonds, pine nut, carrots, and oatmeal. I had purchased a new set of mice for a spare tank I found in my basement. At the time they seemed healthy. I had even paid extra for a female who had just weaned a litter and was already pregnant.

Needless to say, those three mice became ill. Before they had begun displaying signs I had switched out a healthy male into their tank and the smaller male from the newer colony into a single female mouse's tank (5 gal, too small for more than 2).

In any event, the male I had purchased died randomly. Now his singleton tank mate female is sneezing/snuffling. The pregnant female dropped her litter and then abandoned them all, leaving them to die. I fed her off. Now I have my original healthy male looking pretty bad with the sniffles. My other tank with fuzzy/hoppers are fine.

Is it worth it to treat them for URI? I happen to be kind of attached to everyone. They all have names and I want to give them the best life I can before they are retired. I hadn't intended to feed the breeders, just their babies. I used to keep mice as pets as a kid and, call me a bleeding heart, but I really don't want to cull them.

What would be safe to give them without affecting their unborn babies, nursing babies, and the snakes? I was thinking Baytril but not sure if it would work in time to or was safe.

Any advice you can give me would be great! If it comes down to it, I can cull them to prevent suffering but I'd prefer to heal them back up again if possible. Their symptoms are no bloody noses, no bloody tears, just gurgling, almost squeaky wheel sound when sniffing, one is hunched over and sneezing a lot. One doesn't even seem affected but is housed with a sickie. Thanks!