In the wild,
invertebrates make up over half of a chicken’s diet, and Mark and I
have been looking for just the right cultivated invertebrate to use as
homegrown chicken feed. Black
soldier flies would
be great…if we had more food scraps. Earthworms are handy…if I was willing
to lose a lot of my castings as the chickens scratch through in search
of the worms. Mealworms are supposed to be
tasty…but have to be grown on grains. We’ve even considered
outside-the-box solutions like grasshoppers (although I’m not sure
anyone raises them in confinement) and water snails (with crushing the
shells being the troubling point there).
![Silkworm life cycle]()
After years of pondering and
reading, I think we’ve finally found a species worth trying —
silkworms! In his excellent book, Paradise
Lot, Eric Toensmeier
wrote:
“Silkworms
are easy to raise…. We keep the silkworms in a cardboard box,
feeding them fresh leaves twice a day. When there get to be too
many worms, which are full of fat, protein, and calcium, we feed some
to the chickens. By the time they reach about two inches long,
they are mostly made of silk and lose their food value for chickens.”
Toensmeier goes on two
write that he lets about twenty of his silkworms reach adulthood and
lay eggs, and the cycle continues. When mulberry leaves are in
short supply, he simply puts the eggs in the fridge to delay hatching
until more leaves have unfurled.
I’m not sure why I never
considered silkworms as chicken feed. They have a long history of
being fed to people and animals (especially pigs, chickens, and fish)
in China, and I recently read a vivid description of the place of the
silkworm on a nineteenth-century Chinese farm in the fictional Dragons
of Silk. In
fact, the worms are thoroughly domesticated — probably even more so
than the honeybee — so they’re easy to raise.
![Feeding silkworms]()
Various modern studies have
explored the possibility of feeding silkworm pupae to chickens, with
most finding that silkworm pupae can replace between 10% and 20% of a
chicken’s diet. Feedipedia reports that fresh silkworm
meal is 55% protein (although about a quarter of that is indigestible
chitin), while on the negative side, other sources report that the high
percentage of fat can impart a bad taste to eggs and meat if you feed
too much. These large-scale studies focus on the less palatable
life stage of the
insect merely because it’s a byproduct of the silk industry, but I’d be
tempted to follow Toensmeier’s lead and feed silkworms at the
caterpillar stage.
Stay tuned for another
post on choosing the best kind of silkworm eggs and raising silkworms
at home.
