Seemingly undigested food - feces

[indyrebell]

My newest ferret-girl has been having regular healthy excrement for 3 days, but then today her poop is a bit green, mucus-y, and piece-y. Very UN-normal. I'm worried and am not sure if this is because the store fed her different food (I am feeding her Marshall's currently) or if she's stressed or if something is actually wrong with her... She seems in good spirits still, but this is my first ferret and I have no idea what should be alarming or not. ):

[indyrebell]

The food I feed my cats IS the same size as the green-bits and is ALSO, green. But I haven't given her access to it unless the cats threw up and she then ate it.... But the other pieces are still light tan-and not normal either.

[Sherry]

Any change in diet or stress can definitely cause this. But why would a pet store be feeding your ferret?