I read somewhere here that the seeds in grapes are toxic to chickens. The back of my property is a hedgerow of wild berries and grapes, totally tangled and not at all easy to remove. They're probably 30+ years old and enormous. I'd like to let my chickens free range back there but don't want to give them access to something toxic. I have noticed that the songbirds eat enormous quantities of these grapes (all of them in fact) and don't seem to keel over. Any opinion? The grapes do have seeds...