Food can be if there's not enough fiber. What kind of canned food are you feeding? Try adding a bit of canned Pumpkin, this will add some fiber and give the stool more bulk, that may help with the glands expressing on their own. One of my dogs I have to requently express her anal glands - the others I never worry about!
__________________ Momma to King Louie 
Missing my angels  California Lily and  Benjamin Button, forever in my heart |