8 month old labs

Question
I have two 8 month old labs, one male, one female.  They are in good health and are exercised twice daily on the beach. My problem is, how to achieve firm easily picked up stools?  I currently feed my labs Burns Complete food mixed with a little Burns Moist.  They are not overfed but very rarely manage a firm "pick-upable" stool.  I have tried other diets, including a raw food diet, but to no avail. I give them raw bones as often as I can and this does produce a nice easily disposable stool, but they need a handful of bones each per day to achieve this and they are not that easy to come by.  Any suggestions you could give would be much appreciated.  They have not been neutered yet.  They are wormed regularly.

Answer
Have you worked with your vet on this?  Some problems such as giardia can be hard to find.  You may even have to check with a second vet.  

I would be leery of giving a growing large breed puppy bones.  Excessive amounts of calcium can interfere with the body adsorbing what it needs.  They are also rapidly wear the teeth.