In my
last post, I wrote
that I wasn’t sure how many silkworms you could raise on a single
mulberry tree, and that got me wondering whether chickens fed silkworms
would use land more or less efficiently than those fed corn and
soybeans. I don’t expect to be feeding our flock solely on
silkworms any time soon, but it’s an interesting thought-problem when
trying to decide how much space to commit to mulberries.
The hardest part of my
calculation was guessing how many silkworms a hen would have to eat in
a day if they provided her sole ration. I couldn’t find any data
on nutritional value of silkworms at the two-inch stage, so I used
information for the less palatable pupae, which clock in at 2,881
calories per dry pound. Using a lot of rough figures, I came up
with a chicken needing 33 two-inch silkworms per day, or about 12,045
per year. (Silkworms would really only be grown during the
summer, but presumably you could freeze or dry them for the winter.)
If you’re raising mulberries
to be fed to silkworms, you don’t generally let the plants turn into
trees. Instead, you space the plants two feet apart in all
directions and coppice
repeatedly, getting perhaps 16 tons of fresh leaves per acre, which
might be enough to feed 640,000 silkworms per acre per year.
Another figure is less optimistic and suggests you may only get 160,000
silkworms per acre per year.
Depending on which
figure you use, you could raise 13 to 53 chickens on the silkworms from
one acre of mulberries processed by silkworms. In contrast, Gene
Logsdon suggests you can keep one chicken going for a year on a bushel
of grain, and you
can grow about 40 bushels of wheat on an acre. So it’s conceivable
that silkworms could be comparable to grain…if you don’t mind the
work of hauling mulberry leaves to your insects two or three times a
day.
Of course, this is just a
thought problem. On a diversified homestead, it makes sense to
coppice the mulberries more lightly so the bushes provide fruits as
well as silkworms, in which case you should expect to get enough leaves
for only about 15 to 30 silkworms from each bush. (A mature tree,
on the other hand, is reported to feed about 100 silkworms.)
Clearly, I’ll be a bit hard-pressed to come up with enough leaves to
feed the offspring of my 200 silkworm eggs this year since I’ve only
got one hefty and two puny mulberry trees in the ground so far.
So, I let Mark talk me into adding two new varieties to our collection:
- Oscar’s Mulberry (Morus alba)
— Edible in the red stage when they have a raspberry-like flavor, or
in the black stage when they are among the finest flavored of hardy
mulberries. Very early ripening. Zone 5-9. - Silk Hope Mulberry (Morus alba
x M. rubra) — Similar to
Illinois Everbearing, but superior in size and flavor. Excellent
quality with a long fruiting season. Widely adapted, tolerates
drought or high humidity. North Carolina selection by A. J.
Bullard. Zone 5-9.
If silkworms turn out to
be as good a fit for our homestead as I’m hoping, we should be able to
ramp up production dramatically in a year or two. Thanks for
bearing with my flights of fancy in the meantime!
I’ve got a couple of very small mulberry trees growing, and am keen to propagate them around the chicken areas. The idea of coppicing hadn’t occurred to me, but it would be good to keep the trees to a nettable size. I’m sure the chickens and ducks would eat the leaves as well.
Darren — Mark’s the one who thought of it last year, but it makes lots of sense, especially if you start adding silkworms to the mix. I’ll be curious to hear if your ducks and/or chickens like the leaves — they’re definitely supposed to be high in protein.
I just learned about silkworms yesterday while purchasing supplies for homeschool. The school supply store had them on the counter for school teachers to allow their students to watch the moth life-cycle. I bought two dozen for my sons to try making a little silk.
We have a number of Mulberry trees and also a small flock of White Plymouth Rocks. I generally grow Barley and also mix clover with our lawn to generate nutritious grass-clippings. We let the chickens graze for bugs, etc, but of course, finding a sufficient good protein supplement for chicks and layers is always a challenge.
So when it dawned on me that these ancient, domesticated insects might be the perfect solution I checked the internet and was pleased and inspired to see your site and efforts! When you look to silkworms as a protein supplement, and even young Mulberry leaves or other (waste) vegetation as part of a poultry diet, the numbers for production are much higher than your low estimates, I think. But I will be happy to return with my results after I have made more accurate calculations! Thank you for your site, ideas and efforts!
Mark — I’ll be curious to hear how your experiments turn out!
My goats couldn’t get enough of my mulberries and leaves, and green wood, before popcorn disease destroyed all the fruit and I cut off all the branches. Then the goats ate the new coppiced sprouts and well… that was that.
Eric — Mulberries do seem to be the permaculture tree (at least according to Mark. 🙂 ) If you ever get the opportunity to let one grow up above goat height again, maybe you should pollard it? You’d get all the benefits of coppicing without the goats automatically eating every new shoot.
I just came up with what I thought was my original idea of silkworm & chicken 🙂 just about to start calculating the output when a quick google returned this. thanks!
I hope to do my mulberry as a understory to a canopy of grafted walnuts.
I’m also planning to do black soldier fly & siberian peashrub
to give the chickens some varety..