Often pieces of kibble get stuck in the machines that make it and end up getting baked several times until they are charred and then they break free and end up in a package. You even find this sometimes in human cereal (ever seen an extra dark shriveled Cheerio?)

That is probably what you found. Just pitch it and don't worry about it.

Or, send it in an envelope to the dog food manufacturer with a complaint letter. They will probably say the same thing but send you coupons for free or cheap dog food as a customer service gesture.

I don't believe it is an over-baked processed piece of kibble, since it has a perfectly cylinder shape, smooth and compacted (shaped just like manufactured rat poison or rabbit food). Their kibble is a completely different color, shape, size, all together.

SOunds like a rate dropping. Why do you jump to rat poison? Rat/mouse poison pellets are usually light brown or green. Use google images to search on rat poison and you will see no black pellets.

For testing, contact a testing lab.

Talk to your vet. Not sure how a dog acts nauseous.

rats CANNOT vomit and dogs can. Thats why rats die and dogs get sick. Both eat the poison.

I found a small black pellet in the bottom of my dog's food bag. Does anyone know if rat poison comes in that form or any other type of poison? My dog was acting nauseous yesterday. Or does anyone know where/if I could get it tested for poison? Thank you.

Also, it is definitely NOT mouse droppings. It is a manufactured pellet of some sort.