if the stool gets better then you should have nothing to worry about...rice and chicken is easy to digest and will help with regulating her stool. If you continue to see mucous take a sample to the vet check for coccidia and giardia check, a bad bacteria can bring a puppy down fast. Since you have such a little one I would have some rebound on hand...here is the link
http://www.vetmeddirect.com/i_009NPS...n-32-ounce.php... it comes in chicken or beef flavor
hope this helps