teeth grinding and terrible poo =/

Question
i have 2 female rats and am extremely new to owning the fascinating creature. I'm not sure how old they are, but I've had them for about a week. they are not altered. i got them from a pet store. carefresh bedding. feeding them fiesta (picking out the corn) and the pellets that the store recommended i try to always make sure they have the pellets but only give them the fiesta at nighttime.

but i have a few questions.

1. i know that Atira needs to get used to being handled and get used to me. but when i do finally get her to come out of her cage, she poops EVERYWHERE, which also I've come to understand is a result of one very  nervous rat. My concern is that her feces is pretty soft (not diarrhea) and it smells absolutely terrible. My other rat will poop occasionally but it doesn't smell bad at all.

2. Both Sasha and Atira have been grinding their teeth a lot the past few days. at first I'd hear them every once in a while at night and in the mornings. but lately its been more often.

3. The rats are in separate cages right now. i know that everything i read says they should be housed together. The store i got them from had them in separate cages. (Sasha is a blue and Atira is a tan hooded fancy) I let them play on the bed together and stuff but i just cant tell sometimes if they're fighting or playing.

this is a lot i know - but it is really hard to find consistent answers to my questions. Every website says something different.

Answer
The poo is normal - she's stressed, and thats a-typical 'stress-poo' as almost everyone calls it. When she settles down around you and relaxes, her stools will return to normal. Unless it looks bloody or abnormally hard; don't worry about it.

Teeth grinding, or bruxing, is entirely normal.. it's a sign of contentment usually.

I'd try to introduce them, just to give them the company of each other. Do it slowly.. introduce them on neutral ground and see how they do. Completely clean, sanitize, and rearrange the community cage before putting the girls in there together. Then remember the Golden Rule with rats: No Blood, No Foul! If they look like they're fighting, provided nobody is bleeding or on the verge of bleeding, don't break it up. Let them work it out. In the end, everyone will be happier for it. The longer you wait to introduce them, the harder it'll be.