Have you ever heard of a doctor treating disease this way? When a doctor is in the mall and sees somebody coughing and sneezing, they don’t come back and leave a bowl of candy laced with Tamiflu.
That would be a bad idea for a number of reasons. The doctor can’t make a diagnosis from a glance, doesn’t know the person’s weight, doesn’t know if they might be allergic to an ingredient, and doesn’t even know if they’ll be back in that shopping mall any time soon. Medicated candy could easily go to the wrong person, including a small child who would be poisoned by an adult dose.
The same is true for wildlife. It’s dangerous to put medicated food outdoors and simply hope for the best. An animal that is sick enough to need treatment is sick enough that it needs to be captured and brought to a wildlife rehabilitator. There, it can deceive a correct diagnosis, an individualized treatment plan, and all the supportive care and monitoring it might need.
If you have spotted a sick animal, the kindest thing that you can do is to set a cage-style humane trap and bring the animal to your local wildlife rehabilitators. Please don’t try to medicate a wild animal yourself.