Correct me if I'm wrong ( Fancy would know) but corn is a " Hot feed " meaning it will increase body metabolism and make the girls hotter. This is why cracked corn is fed to race horses
Corn has little nutritional value. It is said to change eye colour in birds and most showies avoid like the plague.
In my search for ' natural ' chick starter I found that most of the organic products are essentially crushed corn . That is a problem especially with silkies as they are renowned for being lousy at absorbing vit E and suffering wryneck as a result. Corn is likely to make your birds fat and unhealthy, I call it crack for chickens.
Oats are what we use to give the boys some extra spring in their step. Corn , barley and sunflower for fattening up.

http://www.browneggblueegg.com/Article/CornAndSilkies.html