Cure of hard stools?

What could be the reason for having hard stools?

How could someone cure it?

How to naturally increase the secretion of digestive enzymes?

I am taking homemade probiotic drinks, Magnesium Bi-glycenate, Magnesium Citrate, Calcium Carbonate, Zinc, Slippery elm, Licorice root. I drink adequate water, take fibrous food, and do physical activities. However, all these are not helping.

Kind regards