I do exactly that. Not sure if you are getting sprayed or irradiated seeds, but my experience in the US at my mother's house and considering how many bird seeds fall and sprout, they seem totally viable.
I also sprout for my rabbits and myself, sometimes I do it with soil and sometimes without. I find that if I'm eating it myself I don't want the seed hulls in there, so I often spread the sprouting seeds out in a sprouting tray with a bit of dirt, that way they all grow up in the same direction and I can just cut them all when they're the size I want them. In fact that usually works out best, as I get the little sprouts and the second round (after "thinning") can get big and the rabbits can enjoy them a bit bigger than I like them. In fact I have a bag going right now for this very purpose.
Funny you should ask that.... I am picking up a 25 pound bag of black oil sunflower seed in town today to do just that. I started doing that about a decade ago maybe a bit longer, I had an old 50 pound bag of sunflower seed that I was mixing with my chicken feed. I noticed quite a few sprouts late one winter and thought... I wonder if I could grow a patch of these...
Early spring I raked some ground off and roughed up the soil and hand threw out seed and raked it in. I planted about 30 pounds that year and had several thousand plants in a small area of maybe 300 feet by 300 feet. The next year I got a bit more carried away and planted a 50 pound bag of them in half a dozen areas, as I noticed the year before how popular they were with the goats and deer. I thought maybe I could use them to distract from the eating on my garden areas. Worked quite well really.
I have a hillside to the east of my southern forest that I raked all the pine needles off of and I am going to plant that in with the black oil sunflower seed.
Be forewarned, these seeds do come with insects that like to eat sunflowers, you might keep them a distance from your garden. You might also switch up where you plant them each year to help reduce the probability of getting a new invasive pest started from them or something.
It is not hard to get a small "field" of these sunflowers growing, I like the gorgeous color, I have harvested some heads before and saved them, though generally I have just let the goats and birds eat them down. The second year generally has a fair bit of volunteer plants popping up though nothing like when you plant. You can use soil that is bare and rake the seed in, or you use ground without much cover growth and throw out the seed and lightly disc it, in a yard setting you could run a lawn mower thatcher blade through and then throw out seed maybe. Not hard to get it planted even on a large scale.
Thanks for all of the responses. So far I see that people are using dirt to grow sunflower microgreens and I haven't seen anyone sprouting sunflowers with just water in sprouting jars. Maybe that means that it is not done for a reason. I'm still searching on that issue. I do not want to use dirt as it is just not convenient for my situation.
they sprout just fine in a sprouting bag (I start in a jar and move to a bag, it's easier for me and I find they don't get as nasty smelling). Bigger volumes, not sure how that works, but I'm pretty sure I saw sprouting setups on youtube for rabbit feed that used large trays, so maybe that might be an avenue.