Thanks for the replies. I thought 24 hours sounded right but when the vet said 72, I just had to get a second (or third or fourth!) opinion.
Our mystery seems to have worked itself out for the time being. Not solved but my boys all seem a lot better.
I'll try and sum up what happened without giving you all a giant wall of text to read. I did warn ya that it was a long story!!
Three unneutered males; 10 months old. Strictly indoor cats. Beefy, Cheese and Porkchop. Aprox 8-10 lbs
They eat/ate: 9 Lives canned (switched to) Friskies Tasty Treasures canned for dinner and Friskies Favorites dry/Purina Indoor Natural dry for grazing. Yes, I wish I could feed them expensive Blue Buffalo ect but it's just too costly and my husband won't go for it.
A little background:
The mother is a feral that has been coming through our yard for the past two years and still won't let me very near her. She'll accept the food I give her but that's about it. Last November, she had her kittens under my bay window in my backyard. The plan was to adopt them out via the Humane Society, flyers, a local pet shop ect. I made a bunch of calls, asked around, tried pretty hard to find homes for them but found nothing that seemed right. At about 5 weeks old, the mother started wandering around more and leaving them alone in the cat shelter I created under the window for them. Except in November, it gets pretty cold here in Wisconsin. I felt so bad for them that I grabbed them up on the 6th of December before a snowstorm and brought them into my basement. I already had 6 of my own, (older, spayed, immunized females) so I know I shouldn't have kept them, but... We're all a big happy cat family now. The boys have their own room for sleeping at night so the girls get a break from them. All the cats have been in great health, nobody has given me reason to call my vet and things have been going really well. The first vet appointment was scheduled for the end of this month for all shots and neutering. As in, right before the mystery illness presented itself.
So. Fast forward to the 8th of this month. Saturday night. Cheese vomits rather violently. Okay, cats puke sometimes; I don't freak out. Was right before bed so I clean it and him up, give some cuddles and put the boys to bed. Next morning the husband says 'Hey, I don't wanna worry you but Cheese has, um, a wet rear end." Indeed he did. Clear mucus coming from his little butthole. Continued all that night, not a huge amount but certainly not normal. Husband says not to worry, his UNSPAYED female used to do the same thing. "Um, yea, hon, she was doing it for a different reason." He says not to call the vet just yet; Cheese will be fine. Cheese vomits some more. Like three or four times a day till I'm freaking out and posting here, telling you guys about his mucus. This goes on for almost TEN DAYS. Husband still insists he's fine. He's still eating and pooping, but it's loose. Finally I ignore what my husband says and on Friday, call my mobile vet. She says she'll come Monday but on Saturday, bring her a few stool samples. Remember, we're at SEVEN days of this now. Zero treatment. I collect samples from Cheese and Beefy (who's suddenly got the mucus and very loose stool). I notice when he's falling asleep, his neck seems to spasm a bit. Raises his head to the upper left and twitches a bit. This has never happened before.
Cheese perks up Sunday evening and when Dr. Rossi arrives on Monday morning, Cheese is actually doing a lot better. After looking at the fecal samples I've given her Saturday afternoon, she finds no parasites. She examines Cheese, finds no lumps or anything alarming in his abdomen, but he's dehydrated (gets subq fluids), running a fever (Penn G injection antibiotics), and 5 days of Flagyl for me to give him the coming week. Beefy is now vomiting too. She gives him the same as Cheese but adds a shot of Cerenia for the vomits. Pork Chop seems fine, but he did have the butt-mucus on Thursday but no vomiting. He gets some Penn G anyway and I'm told to give all three boys the Flagyl for 4 days. That's what I do. However, Beefy's shot of Cerenia wears off and he starts vomiting again. About every 4 hours. He's also doing the falling-asleep-head-twitching thing. I call Dr. Rossi and tell her he can't keep the antibiotic pills down and they seem to make things worse. She agrees I should not try to give them to him anymore. She comes back on Saturday morning (the 22nd) and gives Beefy more subQ fluids, Convenia (the crazy antibiotic injection), Kenalog for the GI irritation, and more Cerenia. Throws in some a/d canned food (he thinks its gross). She says to call her every day and we'll see how it goes. He hasn't vomited since, it's now the 26th. Thus my creation of this post the other day. All the boys have perked up, everybody's stool is getting back to more normal shapes, they're playing again, grooming, heads aren't twitching when they take naps anymore and things seem pretty much back to normal. So... that's my story.
TL;DR version: Anal mucus, vomiting, no parasites, head twitching when falling asleep, eating normally, but lethargic. Given subQ fluids, antibiotics and anti-vomiting shots. Seems like a poisoning, a blockage, or a virus. If it was/is a virus, it seems to pass in 10-ish days. No blood work has been done. Why? Good question.... Other 6 indoor girls are perfectly fine. No symptoms at all.
So this is VERY long and I'm sorry to actually have typed so much here and if you read it all- wow. Thanks! o.o
Do you have any ideas about what this could be?