A typical day in the life of Synaptoman. Thursday saw us finally introduce chickens to our commercial Aquaponic site. Chickens are the missing link, that will provide the much-needed nutrients, reduce the feed bill for the Tilapia and yield eggs for consumption or sale. We had a few choices. namely day-old chicks or fully grown fowls and broilers or laying hens. We eventually settled for laying hens, but the obvious question arose. How many chickens?
Before I answer this question, let me backtrack a bit and explain how chickens are going to fit into an Aquaponic setup. For the squeamish just skip the next paragraph.
Tilapia eat anything (very much like prawns and crayfish) but being mostly vegetarian any substitute feed would have to be from a vegetable source. Enter chicken dung. Tilapia thrive on this readily available source of food and are grown worldwide below chickens, ducks and numerous other poultry. The chicken dung in the water is also an excellent source of additional nutrients for the plants. Our plan is thus to place chicken coops over one of our Tilapia ponds.
Well, back to how many chickens. From a brilliant publication entitled, “THE VERTICAL FARM, Food Production of the Future” by the Columbia University Department of Environmental Health Sciences, (see their website here) I discovered that a laying hen poops 40 lbs per annum. This is 18kg per year or about 50g per day. In the pond we have 1500 fingerlings of say 25g each. 25g x 1500 fish = 38kg of fish. If I want the “poop” component of their diet to be 1% of their body mass per day I then need 380g of poop. Divide this by each hens contribution of 50g and we could use 380 / 50 = 8 hens.
I “chickened” out of this number and used 6 laying hens to try out the system. What concerns me is not so much the chicken dung which I know will be eaten, but all the other debris, feathers, feed etc clogging up my system and fouling the water. I am also concerned about dissolved oxygen (DO) levels. This is what the chickens look like suspended above the Tilapia pond.
We have 40 free-range laying hens available so they’ll each have to do a few hours of toilet duty a week to keep things flowing.
I performed water quality tests this last week and the system is looking good, with the bacteria in the gravel growbeds maturing nicely and starting to do their job, ie converting Ammonia to Nitrites and then to Nitrates which can then be taken up by the plants. Here are the results of the water test.
The readings are;
pH 7.5 – 8.0
At the other commercial site I have decided to use a reject swimming pool of about 25000L as a sump and we spent the week digging a suitable hole. I met the pool guy at Simola and guided him down the torturous pass and up the other side with the pool on the back of a trailer. I had to drive ahead with my hazard lights on and warn oncoming motorists of a wide load. This road, in places, is hardly wide enough for two cars so a 3.6m wide swimming pool might just present a problem.
Here is a shot of the pool coming around a hairpin bend with a sheer drop off on the one side.
We eventually got the pool to the site and continued digging the hole. It’s hard work and we are now into a solid clay layer.
On Monday the pool will go in and we’ll start planting the poles for the growbeds.
Enough for now
And a VERY Happy Birthday to my daughter, Janys in the UK.