You really should be feeding them chick starter for chickens. Chicken & turkey chicks require different nutrients to develop properly.
Per TSC website: (similar info can be found on Hatchery websites also)
This DuMOR Chick Starter/Grower 20% Feed is a complete formula for starting chicks, ducks, and geese up to 10 weeks of age and for growing turkeys and gamebirds from 6 weeks to market or laying age. Premium nutrition at the correct life-stage results in strong healthy, productive birds with beautiful plumage.
Designed for chickens, ducks and geese from 0 to 10 weeks of age
Designed for turkeys, quail, pheasant and chukar from 6 to 12 weeks of age
Provides essential nutrients for optimum development
Additional vitamins and minerals are not required
http://www.tractorsupply.com/dumor-reg-chick-starter-grower-20-feed-50-lb--5078210
Complete Poultry Rations
Starter Feeds
Newly hatched chicks ages 0-10 weeks should be fed a starter diet with a protein level between 10%-20%. These rations are formulated to provide proper nutrition for growing baby chickens. Higher protein starter rations (22%-24%) are reserved for meat birds such as turkey, quail and pheasant. This higher protein level maximizes growth for broilers and roasters, but is not necessary or desirable for egg laying chickens.
Grower Feeds
At 10 weeks of age, a grower feed should replace the starter feed. Grower feeds are typically 15%-16% protein, and are designed to sustain growth to maturity. The higher protein content (20%), in starter/grower feeds is recommended for growing game birds.
Layer Feeds
Layer feeds are designed to provide optimum nutrition for birds laying eggs for consumption. Layer feeds contain 16% protein and have increased levels of Calcium, for proper shell development.
Layer feeds should be fed starting around 18 weeks of age, or when the first egg is laid, whichever comes first.
http://www.tractorsupply.com/content/knowhow/chicks/livestock+care+-+feeding+poultry