Ok, I get questions from people new to chickens all the time on how to feed them. I could write pages on feeding, but the following article will discuss very basic feeding methods.
There are basically 3 age groups of fowl; chick, young fowl, and mature birds. To match these 3 groups there are 3 different feeds; starter, grower, and finisher. (I know, I didn’t mention layer feed, but I will discuss this later) All you need to do is match the feed to your fowl’s age.
Now, what if you have several different age groups of chickens all together? Ok, this is simple, just feed them all the feed you would give the youngest birds in your flock. If you have adult birds with chicks, feed them all starter. If you have adult birds with young fowl, feed them grower.
What about my laying hens, how do I get them the calcium they need? Layer feed has the extra calcium that hens need to lay. The problem is, that the extra calcium is not good for roosters, young birds that aren’t laying, and chicks. The solution to this is to feed them all like I described above, but provide a dish of oyster shells for the hens that are laying. This will allow the hens to get the calcium they need, without the rest of your flock being forced to eat it like they would if you used layer feed.
What about grit? If your birds are on the ground, whether it is free ranging, or in a run, they won’t need grit. If your birds are not allowed access to the ground, you will need to provide grit to them for proper digestion.
What about treats? Treats should not be a regular part of your birds diet, but if you feel you must, try things like green vegetables, grass clippings, and fruits. Corn should be used very sparingly as it is high in fat, and low in nutrition. Corn should not be used in the summer months at all, because it will make your chickens over heat trying to digest it. On the same note though, whole corn is a good supplement in the cold months, because it will help keep your birds warm.
There is much more I could discuss, but this should give you a good place to start if you are new to chickens. You can see more about feeding, and nutritional requirements of chickens at the Ultimate Fowl Forum.