I have been buying Layer Pellets for ages for my flock of around 22 hens and on every bag of food i buy it has a label saying how much protein vitamins etc. and on this label it says NO antibiotics or growth promotants added and i believed this but recently I've been told that i should use mixed seeds because they have no antibiotics added and that pellets still have antibiotics either purposely put in or swept in with the floor shavings and just added with the pellets.