The BOSS I use is the one sold by many stores for wild bird feeders. Shell on, whole black oil sunflower seeds will sprout fine. Look in the garden section of your favorite local hardware store (Ace/True Value), home improvement (Menards/Home Depot/Lowes) or feed store (Tractor Supply/Farm & Fleet/Rural King).BOSS question. The only Black Oil Sunflower Seeds I can find are at Walmart and say "added vitamins and nutrients" is this normal? Is that the only BOSS out there?
As to the disinfecting the sprouts for your chickens, I rinse my seeds really well at the beginning and then twice a day until I feed them. I never disinfect the sprouts, only the trays or bowls between batches. I was showing my daughter how long it took for different seeds while she was here for Christmas. We started kamut, barley and sunflower seeds on Wednesday evening. Soaked the kamut and barley for 5 hours and the sunflower seeds overnight. By Saturday, the kamut and barley sprouts were big enough to give to the flock. By Sunday the sunflower seeds were ready. I feed when the sprout just starts to show (the roots start the second day) which was three days from the kamut and barley and four days for the sunflowers.
YMMV-your mileage may vary.........the disclaimer that all car dealers used to put on their advertising...
