Unhappy new home

Question
Hi, I just recently bought a new rat. She is a dumbo and she is very young! I brought her home just yesterday. I have 3 other rats. 2 are about 1 year and a half and I got them when they were a year so I've had them for 6 months and one is 6 months and I got her about 3 months old. My two older ones are a bit less social because they weren't handled well before I got them and they are now just starting to warm up to me. My younger one is very social and loves to be with me at all times. The one I just brought home seems to be very distant from them, even though all three of my ratties greeted her very friendly. She appears sick with diaherra and I've watched her and since she has been with me she refuses to eat or drink. I had to force some apple slices in her mouth so she gets something inside her. She doesn't like to be held and she will avoid me. She is always sitting by herself while the others are playing. I don't know what to do, if I should take her back, put her by herself. She seemed fine at the store. ]:

I also have another question. My younger rat, her name is Kizzy had something wrong with her about a week ago. I was cleaning their cage and I clean it with just warm facet water. And when I finished she started to cough up a clear gooey liquid. She wasn't energetic like she usually is and she would lie down in her bed very still and wouldn't move. She is great now! I fed her some apple slices and about 5 mins later she was perfect, I don't know if she was just sick, I just wanted to know what might of happened.

Answer
To begin with, and I hate to sound all stuffy on you, but you really should review and adhere to Quarantine guidelines. They are for your new rats & your existing rats safety! Here's a handy, very well put article here: http://ratguide.com/health/basics/quarantine.php

Your new dumbo does not sound well. It could be something as simple as endoparasites or it could be a upper/lower respiratory infection and that's the only symptom you've noticed, or she may have been fed far too many sugary foods and just have a bout of otherwise harmless diarrhea. What diet do they normally get? Be careful giving too many fresh fruits and veggies. The more sugar and/or water in a food item, the more likely it is to cause diarrhea, which in turn dehydrates the animal and is very likely to cause death if it continues and they are unable to re-hydrate. I recommend fresh fruits and veggies in small amounts only every few days -- if you already know this, then great! you're a step ahead of many other rat owners!

If you're going to encourage her to eat, avoid the fruit and instead pick softened kibble or lab block, baby food, meat pastes and other high-calorie but low sugar & easier to eat foods. For rats not interested in eating, soft, mashed foods are usually the way to go. Try to avoid forcing her mouth open and instead try to encourage her to eat on her own. Forcing her to eat may increase her risk of aspirating, choking, or becoming more fearful and stressed.

As far as Kizzy, she may have aspirated/choked on something and what you saw was the aftermath of her choking it back up. Rats cannot vomit, however they can regurgitate. I know, it sounds like doing the same thing, but vomiting is once food reaches the stomach and regurgitation is when food is in the throat (or in birds, the crop, a pouch between the throat & stomach). If something is stuck in the throat and a rat is gagging, often they CAN create enough saliva to hock it back up on their own. If she's acting fine now, I'd suspect that's what it was. Try to think back and make a note of what it was she was eating that day and perhaps be very careful feeding that food again; or if you feel the chunk may have been too small to chew/too big to swallow, find a happy medium between those two sizes to avoid future choking.

Good luck;