"Dogs require fairly high levels of calcium, and yogurt absolutely won’t cut it. Here’s a quick example: My own 75-pound dog has a daily requirement of 1,840 mgs of calcium, and since I use quite a bit of fiber in his diet in the form of brown rice, I want to offset any absorption issues and ensure that he gets about 2,000 mgs per day, or 14,000 mgs per week. His weekly diet alone—turkey, liver, sardines, brown rice, ground lamb and acorn squash—only provides 1,750 mgs. That means I need to add over 12,000 mgs of calcium; in other words, more than 40 cups of plain yogurt.
Calcium supplementation is always necessary unless you are feeding raw bones. I recommend using a commercial carbonate or citrate form of calcium, or an eggshell crushed into a fine powder—one teaspoon of this powder (about 5.5 grams) equals roughly 2,200 mgs of calcium carbonate. To use eggshells, rinse them well and then bake for about 10 minutes at 300 degrees; use a small grinder to make the powder. Bone meal can be used if there is also a need to add phosphorus, but many homemade diets supply plenty of this mineral."
Given this information, I make my own calcium for the dog's food. It's so easy and is made with one simple ingredient you would throw in the garbage or compost anyway! Every time I make eggs, I rinse the eggshell well and keep them in a container in the fridge. Once I have accumulated about a dozen egg's shells, I put them on a baking sheet and bake according to the directions in the above paragraph. Once they cool, put them in a spice grinder and grind them into a powder. Store the powder in an old prescription bottle and use 1 teaspoon in every pound batch of dog food.
Easy. Inexpensive. Healthy and necessary additive to the dog's food.