Great thoughts on the subject matter.
Let me look at it with two different angles then. We can look at the scientific aspect and the playful angle.
To keep it as simple as possible, they have manufactured organic addicitives that with small amounts, such as one gram spread out through 1 kg of food, can provide your dog with the added nutrients for them to grow a healthier coat. (compressed vitamin b2, so on and so forth.). These addatives take up such small amounts of space that it doesnt require your animal to eat larger portions. Vitamin B2 isn’t necesarly something that would be that beneficial to rabbits, but a composition of other nutrients could benefit rabbits. Anyways, away from the scientific side is there anything you would want for your rabbit? Without being precise to more hay etc. Strictly an adjective you wish your rabbit would be “more of”, like hyper.
Would a catnip for rabbits interest you ? Rabbits in new places, rabbits who are being relocated to new homes are often times anxious. Would natural calming agents for rabbits be something that could benefit them when they are being rehomed?
just some other angles to look at, maybe I didn’t express myself properly in the begining.