Vomiting Cats

A couple of days ago my indoor/outdoor cat Duke threw up twice and has seemed fine ever since. Yesterday (01/02/15) my kitten Baelfire (approximately 4 months old) ate and threw up twice. He has not eatn or drank anything since (to my knowledge) and has been throwing up yellowish green liquid ever since. I took Baelfire to the vet this morning (01/03/15) because he was sleeping a lot more, not being his playful little self and vomiting every few hours. Vet gave him fluids, took his temp (no fever), gave him something for the nausea. He has been doing better interested in playing but not as active as usual and still not eating/drinking up no vomiting. Now two of my other cats Cooper and Billy have thrown up a few times. Duke the first cat to have thrown up a few days ago hasn't thrown up since, he is acting normal, eatinf/drinking not throwing up. Cooper and Billy have thrown up a few times today but are still active eating drinking and seem fine. I have no idea what is going on. Vet did not have much to say. I just want all the vomiting to end and my babies to get to feeling better. Any advice would be greatly appreciated. I feed my fur babies Earthborn holistic and have been using the same brand for over 2 years. I called the pet store and there is no recall. They offered to exchange it for a different bag so I will be doing that tomorrow.

Stop feeding that food and pick a new brand of food. Cat food companies are not required to do a recall. It is voluntary. So even if a batch makes a few cats sick the company won't care.

Did the vet do a fecal exam to check for parasites? Looks like all the cats have some sort of bug. It could be from the food but it could be parasites or a virus.

Is it possible they've gotten into something like a plant (especially being indoors/outdoors) or some garbage that has upset their stomachs?

Otherwise, if this vet didn't have much to say or wasn't thorough in examining the cats for parasites or anything else they may have "caught", maybe get a second opinion from a different office. Sometimes it just takes a fresh pair of eyes to see something your regular vet overlooks.

Unless the vomiting started with a new batch/purchase of their regular food, I would say to look into external sources first.

She said Baelfire's intestines were slightly inflamed and bladder was good. Switching cat food tomorrow. The pet store I have been shopping at for years is kind enough to exchange it. Tomorrow I will be purchasing rice and low sodium chicken broth in hopes they can keep in down. My only two guesses of what could have possibly caused this would be 1. My shower has been draining slow so some soap is left behind. I have caught the Baelfire and Duke in the shower drinking the water but really havent seen the other 2 in there. 2. I have a leak in my roof in my bedroom I can't fix until weather is better. I keep catching the little one drinking it but i don't think the other 3 get into it. I have 1 plant they have messed with before but didn't get sick.

Only 1 is indoor/outdoor and he is the only one not throwing up. He threw up a few days ago twice but has not thrown up since. He is eating and drinking as normal.

Baelfire, Cooper, and Billy are all indoor only cats. Duke is indoor/outdoor. I haven't let him out in 2 days at least to monitor him. Duke is the only one not throwing up. The kitten Baelfire is my biggest worry because the other 3 are all eating and drinking willingly and only 2 of those 3 are getting sick. I hope i can get the kitten to eat some rice and chicken broth (vet recommendation) i know the other 3 will be all over it.

Is there anything else new in their environment?  new floors, furniture? new beds? cat tree?

It sounds virusy but I'm no vet. Don't start them on the new food all at once. Do it gradually or they will get ill.
I hope they all get better soon.
It's like when kids are ill, siblings, it goes from one to the other.
I'll be thinking of you.