well 90% of my hens roost in one big pine tree for about 4 years, and its dry as hell ( even tho its been raining like a mofo ) and i put maybe 1/2 a shovel full ( mixed with dirt ) about 3-4 inches around the stalk of the plant..well bat guano is notoriously bad for people's health, so I dont see any problem with bird shit, Id say just pread it out in the sun and dry it before mixing it into your soil, so you can reduce the smell for an indoor,
havent grown outdoor yet, but when i do I plan to shit in the hole, haha