I make my cats' food at home now too. It took a bit of doing to get my calico with the program, but her sister took to it right away. Now they're happily munching ground rabbit, chicken and turkey . Duck is on order in the next batch of ground meat. The only thing that I don't like is that some of the nutritional additives I mix into their food are doubtless sourced from China.
There are books out that detail how to make suppliments at home. Some I use are brewers yeast and fish oil. I haven’t made ground eggshell yet. Some people even go so far to make their own bonemeal.