Anal Gland Issues are most commonly a result of bad diets with low quality fats and oils (as is found in most all commercially available dry kibbles and canned foods). Feeding a fresh, raw, whole foods diet will help anal glands express more naturally and avoid possible infection from impaction of the anal gland fluids. 

Check out these articles below for more info:

Natural Remedies for Anal Gland Problems in Dogs 

When And How to Express Dog Anal Glands 

Resolving Anal Gland Naturally & Preventing Them In The Future 

Your Pet's Anal Glands - Dr. Karen Becker