Hi folks,

To start with, hemp is the crop grown that produces cannabidiol, or CBD, so I suspect if someone asked you to add hemp to your dog treats, they were referring to adding CBD. 

The question about legality of adding CBD to dog treats in Michigan is interesting as the FDA, who oversees issues with utilizing CBD, has thus far ruled that it is not legal to add CBD to food/feed for human or animal consumption.  You can read through numerous press releases / announcements made by FDA in the past few years regarding the sale of CBD.

However, in the fact sheet, "Hemp in Animal and Pet Feed" from the Michigan Department of Agriculture and Rural Development, they distinguish between animal feed and animal supplements.  My understanding from reading this is that it is legal to sell dog treats with CBD as an ingredient; however, I would recommend you seek legal counsel before investing in production of this product to confirm that.

As to the question about how much CBD to add, I am not aware of research that has been conducted to determine an optimal amount/concentration for animal supplements.  You may want to reach out to the MSU veterinary school to see if they have any research on this or on best practices for how to manufacture an animal supplement including CBD.

I hope that helps, but at this point, as you mentioned, it is a fairly new area with relatively little research.