Apple seeds, peach seeds, apricot seeds, pear seeds, almond seeds, etc... all contain small amounts of biological cyanide (in contrast to synthetic cyanide - which is deadly) in the form that is bound to a sugar molecule that binds to cancer cells only (does not bind to healthy cells). Some health folks refer to this as B-17, which has been shown to take out cancer cells. If you look carefully, many forms of vitamin B-12 also have cyanide bound to it (check your multivitamin).
Personally, I eat the seeds when I eat the fruit... you cannot poison yourself when you take this in small amounts. Chickens and other animals will have no problems when they eat this in small amounts too. Just don't give them a diet that is 100% fruit seeds, and they should be good.
Rich