Tacopaco: You've opened up a hornets nest of naysayers vs. go ahead and do it folks. My response: Your plan would be no different than an auqaponic system, but you're throwing chickens into the loop. I've also considered the same option. Currently, the only fish I have are 3 little goldfish that I keep around to eat mosquito larvae. But, if time allows, they will be invited to a very crudely set up mini-Aquaponics system this winter. Folks grow duck weed and feed it to their chickens: provides a huge source of renewable protein. If the chickens don't get sick from eating duckweed which has been grown in tank water, your fodder shouldn't be much different. Let me play the devil's advocate here: The naysayers, (and I'm not pointing any fingers, because the logic is reasonable, and there would be a hundred other people who would agree with them... say it won't work. And for viable reasons: grains need a clean environment to sprout and not mold, and grow healthy. But, in an aquaponic system. seeds are often direct seeded in a growing medium and start day one being flooded with nutrient rich water from the fish tanks. They sprout. They don't mold and mildew or get slimy. They grow like mad. So, why wouldn't it be the same if that same water was used to sprout wheat and barley? And, why wouldn't those same sprouts grow like mad with the added nutrient from the fish tanks? My understanding is that after day 3 or day 4, when the little sprout has exhausted all of the nutrients packed in the seed, the nutritional value of that seedling actually goes down, until that seedling has an established root system and leaves, to actually start taking up nutrient from the soil, and the leaves are able to create energy through photosynthesis. So, if the goal is to go past the sprout stage, into the fodder stage, the nutrient in the tank water would only enhance the output. So, I say to all, don't say it can't be done until you've tried it and tried it again to work out any kinks)
That being said, there are other ?'s to be answered: #1: Will the chickens pick up any pathogens from the water? I am not an authority, but, if aquaponics are able to grow plants suitable for the human salad bowl, I think chickens would do equally as well with a meal provided from the same system. #2: Since the system would be "planted" much more densely than the typical aquaponic system, and likely to absorb much more nutrient from the water, would your system be subject to wild pH swings, and would the water draining back into the tanks from the seed trays have an excess of tannins or other products from the high density of seeds that would be harmful to the system. Again, I'm not an authority, but have heard plenty of recommendations from folks to save the water from sprouting to water house plants with, so, my initial thought is: I don't think so! #3: The typical aquaponic system is set up so it repeatedly floods and drains the root systems. If they sit in water they WILL rot. So, you'd have to set it up on a slow trickle so the seeds would not dry out, but would not remain in standing water. And those needs would change as the root mat starts to grow. So, I'd recommend that you use the typical aquaponic flood and drain system. So, Tacopaco: I say, go for it, perhaps with a bit more research on a site dedicated to aquaponics. Here's my challenge to you: Start a thread dedicated to the use of chickens in aquaponics, and let us know how well it is working for you, what works, what doesn't and how your system is set up.
Does your flock have access to fresh grass and greens? If so, IMO fodder is redundant. Do you have cold nasty winters with frozen ground and no access to fresh greens for months on end. (Stop it allready, I'm depressing myself!) IMO, that's where fodder can really shine. Also, you mentioned rye as a possibility: I've read somewhere that rye is not as readily digested as a lot of other grains. Any other folks with documention re: this, feel free to weigh in. And, Catryna hit the nail on the head: Shorter grass would be better. My plan would be to feed at the sprout stage: when the top sprout is no more than 2 - 3 x the length of the seed.
I am overly envious!