Safflower seeds are white and a bit smaller than sunflower seeds.
i'm sure they will eat them and most likely won't hurt them. I am a firm believer that a chicken will only things that won't kill them. I have Morning glories all around my run and coop. They are poisonous, cause convulsions and such. My girls wont touch them but will jump up and pluck the gourd flowers that are growning with the morning glories.
I gave my girlies Safflower Seeds mixed with Black oil Sunflower Seeds and cracked corn as a treat. They LOVED it! Actually they would pick all the Safflower out FIRST.
My parrot gets pellets and a seed mix with safflower seeds in it. The first thing she goes for is the safflower so a have to ration it so she won't get fat!
If she can have it, I would guess chickens could too.
My ladies ADORE safflower seeds ! I, too, have to ration them... I discovered that they also love pomegranate seeds (I grow them, but they never ripen enough in my area for human consumption).