Plus the vaccine put a whammy on your immune system.Me too. I used to give the chickens the heads with the seeds ..when.. I had my chickens. . I just placed them all. I'm pretty sick right now with c diff. Struggling to get rid of it. Other things too. Was worried that the chickens could have caused this because I was sick like this last year, but got well without meds. No diagnosis. Tried to figure out what I was doing the same as last year at this time. Hatching! Well, I didn't want to take any chances. No, I wasn't on antibiotics last year or this. Soo..yes, farm animals can cause it...I also have a compromised immune system..and ..I'm old! . I'll plant my sunflowers anyway. Love them!