I found that a very odd question :) but I'm burned out enough from wrapping gifts that I looked it up. The answer is yes, at least to the destroying the viability of eaten seeds part, according to UCDavis edu....Can't speak for how nutritious they might be for your chicks, but blackberry seed compounds are available in health food stores for us human types.

"Chickens, surprisingly enough, are known to effectively digest and destroy all weed seeds passing through their crops and can thoroughly graze back vegetation in areas of up to one acre. Releasing chickens into an area after mature blackberry plants are removed allows them to scratch and peck out weed seeds and effectively reduce the seed bank in the soil"

Hey, I'm the Queen of Odd Questions!

Thank you VERY MUCH for that information.

Just in case you wanted to know... I know the wild birds eat the berries and thus the seeds, and small blackberry plants tend to sprout under other trees, I'm assuming where the birds pooped them out. So I wondered if chickens would do the same thing. Blackberries are Mother Nature's answer to disturbed soil here in the PNW, and I would hate to discover that all my chickens did was scarify the seeds, soften them as they run through their digestive system, then poop out with some moisture and fertilizer to make sure more grow. :-)

Thanks again,

Sue