Just keep in mind that your chickens nutrition requirements are much more critical than your dogs. Especially if they are laying eggs. Any change in feed should be done in an experimental fashion and closely monitored. You may want to offer them grains, greens, protein, calcium, minerals, and grit in some type of a free choice fashion and let them find the correct proportions.
However, if you do this I would recommend you keep the commercial feed available and reduce it slowly rather than trying to change abruptly.
grains - cracked corn is hard to beat for convenience and price but whole fresh living grains are even better if you can grow some.
greens - grass, weeds, vegetable parings
protein - this is the most essential and most costly component, most feeds use soybean meal as it is the cheapest protein source available. It is impossible to make your own soybean meal but you can soak and boil soybeans like you would other beans to make it palatable for the birds. However, you would have to do this every few days because you can't dry store the mash like the beans or meal. Other sources of protein would be fish, bugs, worms, etc... I used to use a net to get minnows and crawdads for fish bait and I plan to get some for my birds that way soon.
You can also grow protein; peas, spinach, brussel sprouts. I'm going to try some fresh peas later this summer.
calcium - if you have layers of course. oyster shells, but I've heard of people substituting a limestone product ? I can't verify the limestone. Keep in mind if you are giving them a variety of greens that are high in calcium they may not touch the oyster shells. As long as their eggs don't get thin or soft it's okay.
grit - my birds get what they need poking around but you can get some of the real fine stuff from a gravel drive or edge of a road and sprinkle it on their feed as well.
other minerals - fresh leafy vegetables, grains, and sunlight have all your birds need. but in the winter this could be a problem if you are planning to totally make your feed. If you live near the ocean you can collect kelp. lay it on the driveway and let it dry and hang it on a nail where your birds can peck at it. Kelp has all the minerals your birds need in almost the exact proportions they need.