Growing Fodder?

I'm gathering some information about the idea of getting some chickens. I would like it to be as sustainable as possible meaning that little to no outside input is coming in. Obviously, I'm looking into free ranging the chickens but would like to know the feasibility of growing the supplemental feed since so many insist that free range foraging isn't enough. I'd like to know about how much fodder would be required per chicken. About how much land it would use (after fixing the soil etc.) Farming insects is also of interest. Any advice will be appreciated!

Oh my, I hate to say this, but it depends.

If you live in a climate where the chickens can forage 365 days per year, it will be a lot different than if they spend 6 months out of the year huddled inside a coop, waiting for weather and fodder to be favorable.

If you live in a very 'seasonable' climate, you will need to think in the 2x2 mind set: warm season grasses & broad leaves X cool season grasses & broad leaves. (By definition, all cereals are grasses.) You will want early and late season crops for every day foraging. The cereals can be harvested, when ready, to help sustain the ladies in the off season. Other crops which are good for off season use are members of any variety of winter squashes (including pumpkins). These are a very dense feed, and the hens seem to enjoy them as much for 'toy' value as they do for feed...this is important in harsh winter regions, where long periods of being 'weather bound', hens may begin fighting with each other (out of boredom) if they don't have something to play with.

I've got a local guy who is selling 500+ pound bins of pumpkin/squash for $25. That's a lot of feed for the buck!
Check locally, as any farmer that has 2nds left over from Halloween, would love to earn a few buck$ on his left overs.

It depends on where you are and what grows well there. An acre of good pasture land can support 1 cow, or 10 goats, or 100 chickens, as a rule of thumb. Some pasture managers have worked out rotations where they put the cows and the goats on some fresh pasture for a certain number of days, and then when the grass and forbs have been grazed and the cow patties are full of maggots, the chickens get their turn at the ground.

I don't have any cows or goats, so the chicken tractor moves around and they get to graze the grass and weeds. It's hard to say how much of their diet is fodder and how much is more conventional feed, maybe half-half. It depends on what's in season in the garden and what I can toss into the coop. They certainly don't suffer from a lack of variety in their diet.

This doesn't qualify as farming insects, as slugs are gastropods, but rotting boards and pieces of tree bark can be used as slug collectors, which are good sources of protein and the chickens will devour in seconds.

First of all, are you talking about sprouted fodder (barley, sunflower, wheat) or grown fodder (beets, comfrey, etc)? There is a large difference between the two.