Congratulations!

You and your family are wonderful for taking in Sada.

She might have diarrhoea from the change of diet, as you suspected. I'd keep her on a bland diet for a few days (plain chicken etc) and make sure she's drinking so she's hydrated.

I recommend a vet check to have a look and test for any diseases, worms etc.

And lots of love!

Good luck and thanks for photos so quickly!