Hi,
Many Shepherds suffer with delicate systems and it is hugely important to find something that will keep them from suffering loose stools.
I think I would be asking my vet for allergy tests, if she is this delicate there may be an underlying allergy that is causing this problem
With regards to feeding a variety, as long as she isn't allergic to anything you can feed the same food, but change the flavours, this is about as good as variety should get to prevent further loose stools!
Dogs are scavengers by nature, she won't starve herself, and she should be kept on a well balanced food to keep her system ticking over nicely.
Here endeth my contribution

...good luck and let us know how it all goes.
Jo
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