Soldier grub bin under poultry coop. How sanitary are soldier grubs?

Lumenos

In the Brooder
10 Years
May 17, 2009
93
3
31
San Gabriel Valley
[ETA: Since creating this thread I have had second thoughts about bringing soldier flies to this property. I have put some of the following statements in red, to indicate that these claims may not be true (or no longer true). I was awaiting some answers from ProtoCulture, but their forum has become unavailable. For updates on this situation, or to read what I have learned since this time, see the soldier grub article in Lumeniki or read this thread starting here or the Black Soldier Fly Challenge thread.]

I'm planning to build a wire/wood bin for soldier grubs, and attach it to the bottom of a coop.*If* I can get a soldier grub colony established, there are numerous beneficial functions of this system. I listed many of these below. (All the quotes are from this excellent fact-packed resource Black Soldier Fly Prepupae - A Compelling Alternative to Fish Meal and Fish Oil ):

*Protect the grubs so they hatch into soldier flies and hopefully return to lay eggs: An expert does not recommend feeding grubs to poultry if they were raised in poultry manure although I have not be able to find a disease poultry can get from this in particular. Soldier flies are difficult to breed in captivity, so the only way you can get more soldier grub eggs, is from wild/released soldier flies. This is the only disadvantage of soldier flies, but it can mean they are impossible/expensive to replace and all the effort and money is spent only to learn this. If I do get enough soldier fly eggs I can use a different grub/worm bin (biopod), to raise grubs that are safe to feed poultry. I can feed these grubs/redworms humanure or things that the chickens don't like all that much like brussel sprouts or citrus, but I don't have a lot of scraps that poultry won't eat.

*Reduce flesh flies: "94-100% house fly control through larval competition and by repelling ovipositing house flies" Flesh flies carry numerous pathogens to humans and poultry (see diseases carried by houseflies, diseases carried by blowflies). Chickens can get a parasitic worm from houseflies, but other edible birds cannot.

*Reduce odor: "noxious odors produced by decomposing manure were reduced or eliminated by Hermetia larval digestion...[t]he chemicals which were affected include the methylester of heptanoic acid, acetic acid, 2-furnaocarboxaldehyde, propanoic acid, butanoic acid, isovaleric acid, valeric acid, caproic acid and p-cresol. These were greatly reduced or eliminated by larval activity within 24 hours."

*Remove nutrients from manure and spilled food, so that rodents (and flesh flies) are less attracted to the area: "Hermetia larval digestion of swine manure reduced nutrients as follows: N-71%, P-52%, K-52%, Al, B, Ca, Cd, Cr, Cu, Fe, Mg, Mn, Mo, Na, Ni, Pb, S., and Zn were reduced 38 to 93%" A neighbor told me that alot of people he knew raised chickens and they always had rats.

*Reduce the pathogens that BSFL are known to reduce: "Hermetia larval activity significantly reduced E. coli 0157:H7 and Salmonella enterica in hen manure"

*Other pathogens are said to be destroyed in heat and apparently BSFL can survive in these temperatures and may contribute to higher temps. [Actually, soldier grubs seem to have about the same heat tolerance as these roundworm eggs, but they are rumored to crawl away from temperatures around 100 degrees Fahrenheit.] Roundworm eggs are the most difficult pathogen to kill by regular composting. Roundworm eggs are killed in a day at over 50 degrees Celsius (122 F) or a week at 45 degrees C (113 F) (source: The Humanure Handbook), but I think that is with composting using microorganisms, so I'm not sure if it is the heat that kills the parasite eggs (that doesn't seem extremely hot), or if the killing is done by the microorganisms that thrive in that heat.

*Reduce the need to clean out the bin by releasing liquid into a drainage area full of high-carbon sorbents like buried wood, twigs, and leaves: "BSF reduce manure accumulations 42-56%...The digested residue is a friable compost-like material with about 24% less nitrogen (net loss of 60%)." The type of manure is not mentioned, but most say poultry manure releases a lot of moisture.

I describe the bin and ask for suggestions in the BioPod forum.
 
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I'll be interested to hear how this works out for you. I've seen those BioPods but can't justify getting one because of the expense. I did think about ordering some soldier grub larvae to put in my compost bin, because I've heard they're even better at composting that Red Wiggler Worms, but the nature of their life cycle means that generally you only get one generation out of them and then they turn into flies and fly away to mate.
 
I definitely interested in seeing how it works out! I have thought about getting soldier flies for composting and let the hens have the grubs. With soldier flies you can compost meat and oils as well, whereas, other forms of composting you can't. I worry about it producing a large number of flies that become a nuisance to our neighbors.
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Oh my gosh! lol. I have tons of these outback! :p
I didnt know what they were lol. I thought they were wasps!
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I think they are annoying cause I always have to watch for getting stung. Can they sting? lol.
I have tons of Larvae underneath the pens. The chickens love them. I wish theywould go away though haha.
 
Hi all,

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It's true that the larvae will mature, pupate, and fly away to mate, but for each female that returns to your pile/composter to lay eggs you will get 500-900 more larvae. The egg laden females are strongly attracted to a colony of feeding larvae so many of the adults that leave will return to lay for you. I'm pretty sure that BSF are in KS and I don't see why you couldn't have regular reproduction through the warm season.

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That doesn't happen. The adult BSF emerge, mate, lay eggs and then die, all within 5-8 days. During that time they don't eat, go into houses, land on people, bite, sting or pester people in any way. On the other hand houseflies live up to 30 days and do eat, enter houses, spread disease and generally pester people. The two insects are very different. I've pupated and released 100's of thousands of BSF on my property and it's still relatively rare to see an adult. They aren't even that common in or around the BSF units I operate and to see more than a few at once is unusual. I keep a colony close to the house for convenience and in 4 years we've never seen an adult BSF in the house.

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No. They are absolutely harmless. I'm curious about your comment that you have tons of them on your property. Do you mean larvae or adult flies? If you have that many adult BSF then you must have 100's of tons of waste available, otherwise I don't see how you could support that size population. As a general rule you would only be seeing the females because the males quickly disappear after mating. Each of the adult females you see represent 500-900 larvae so a large number of adult BSF would result in a huge number of larvae. Could they be some other type of fly maybe?
 
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It's true that the larvae will mature, pupate, and fly away to mate, but for each female that returns to your pile/composter to lay eggs you will get 500-900 more larvae. The egg laden females are strongly attracted to a colony of feeding larvae so many of the adults that leave will return to lay for you. I'm pretty sure that BSF are in KS and I don't see why you couldn't have regular reproduction through the warm season.

"99.6% of oviposition [egg laying] in the field occurred at 27.5 C to 37.5 C (81.5 F to 99.5 f)" I had better hurry to buy a batch for the hot season here. I think you want to buy them a month or so before temps are in that range so they will come back and lay eggs.

Optimum Temperatures

Optimum for Consumption: 35 C. (95 F) (1)

(Note) : Food consumption rates fall with decreasing temperature and effectively reach zero at 15 C (59 F). (1)

Optimum for Mating: “Adults typically mated and oviposited at temperatures of 24 C (75.2 F) up to 40 C (104 F) or more. Booth and Sheppard (1984) reported that 99.6% of oviposition in the field occurred at 27.5 C to 37.5 C (81.5 F to 99.5 f)” (10).

Minimum w/Survival: temperatures as low as 0 C (32 F) for up to 4 hours. (1)

Maximum w/Survival: Larvae survive at temperatures up to 45 C (113 F). (1)

Inactivity: inactive larvae at temperatures less than 10 C (50 F) and at temperatures higher than 45 C (113 F). Survival rate falls rapidly at temperatures over 47 C (116.6 F) (1).

Optimum for Pupation and Emergence:

“Larval activity and growth slowed considerably as the mean daytime temperature dropped below 25 C (77 F) (April-September). Observations indicated that larvae seldom pupated at such temperatures. However, after transfer to 30 C (86 F), some of the larvae used in the sludge processing experiments (see below) then pupated and adults later emerged.” (3)

[Source: Black Soldier Fly: Compiled Research On Best Cultivation Practices, Published 9 July 2008 Research Resources]

I haven't bought them yet because I don't yet have an outdoor bin that is predator-proof. I got a skunk digging all over in my garden and I'd hate to have him make hors d'oeuvres out of my tiny 20 dolla maggots!

I got a small batch before from http://www.silkwormshop.com/shop_phoenixworms.html because they are local and cheap. [Disregard the part in red. I was confused about this 150 degree temperature. You would think I would read the quote I posted instead of relying on a memory of something I thought I read in a forum or blog comment] I thought getting them locally was important because they say "YOU MUST ADVISE US if temperature in your area is above 90 or below 40 degrees; otherwise we DO NOT GUARANTEE LIVE DELIVERY!" and that the small ones survive shipping better than the large ones. That doesn't make much sense if they thrive in composting manure that is 150 degrees F! I followed the instructions and didn't feed them, then forgot about them for a month or so, and all but two died. I think they died from lack of water, although it wasn't "dusty" as they claimed was the only time they would need water. I started feeding those two and they plumped up in no time. They did well in with the redworms.​
 
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"99.6% of oviposition [egg laying] in the field occurred at 27.5 C to 37.5 C (81.5 F to 99.5 f)" I had better hurry to buy a batch for the hot season here. I think you want to buy them a month or so before temps are in that range so they will come back and lay eggs.

One way that you might be able to maximize the expensive larvae is to get them in 2 or 3 separate batches. Get a few now and then get more about the time the first batch matures and then repeat the process again if you can. It's good to have actively feeding larvae in your unit when the first batch emerges and mates. They seem to be able to locate a colony of larvae pretty well so that serves to guide them back to your unit.

I wouldn't be too concerned if your weather is cooler than optimal, Seattle and Vancouver both have BSF populations and I think it rarely gets into the optimal range there.

Anyway, you should have plenty of wild BSF where you are so why not attract your own? Try corn: blacksoldierflyblog.com/2010/04/28/attracting-black-soldier-flies-with-corn/

I haven't bought them yet because I don't yet have an outdoor bin that is predator-proof. I got a skunk digging all over in my garden and I'd hate to have him make hors d'oeuvres out of my tiny 20 dolla maggots!

I would get started now if I were you. I'm using a design based on a 5 gallon bucket that would be fine to establish a colony. You can move it to something larger later. The bucket as designed might help you avoid the issue with the skunk. Because the drainage system is self-contained you can easily move the bucket composter into a shed or garage at night to protect it. Just don't over feed it and it won't smell bad.

DIY BSF bucket composter

"YOU MUST ADVISE US if temperature in your area is above 90 or below 40 degrees; otherwise we DO NOT GUARANTEE LIVE DELIVERY!" and that the small ones survive shipping better than the large ones. That doesn't make much sense if they thrive in composting manure that is 150 degrees F!

They don't thrive at 150º, they must be staying in cooler areas on the fringe of the pile. - "Maximum w/Survival: Larvae survive at temperatures up to 45 C (113 F). (1)"

I think they died from lack of water, although it wasn't "dusty" as they claimed was the only time they would need water.

"Optimum Humidity

Larval Stage Optimum:

“The larvae tolerate saturated conditions well but large larvae lose weight at approximately 1% per hour at 75.5% relative humidity. As expected, the rate of water loss increases with decreasing relative humidity. Smaller larvae are more susceptible to water loss, losing approximately 1.5% body weight per hour at 75.5% RH.” (1)

“Found that the maximum development rates for soldier flies in dung occurs at 70 % moisture levels.”(1)(2)" SOURCE
 
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Have you heard of raccoons, possum, skunks, rats, etc, getting into the grub collection bins on BioPods, or eating the grubs? I think the skunk is after these huge June bug larvae because I had very many of them, and I read they can hear the larvae. Seems like they would love soldier grubs as well. Raccoons could definitely get into a grub collection container on a BioPod, it would seem.
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I tried before with one bucket having a little cheese and other animal products, and one bucket with "only" plant-foods. (Maybe the rice stuff had some animal product in it; can't remember. It was a gift.
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) The flesh flies got into both of them. It just so happens that I got some stinky corn on the cob in the freezer, and I think I have all the parts to build a grub bin like yours. I even have some Velcro loop with no hook, so I can't really do anything else with it anyway.
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Ahhh. Okay that will be plan B, if I can't attract them with corn.
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Err, I'm not sure I am even remembering correctly. It was a post by Rob Ludlow. He may have said 115 degrees. I can't find it now. It may have been a comment on your blog, or a post in this forum.
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Humm it seems it might depend on the "dung". Sounds like an herbivore poop. But yeah, very moist to wet.
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I usually deal with odors by simply covering with a sorbent. (The squeamish should probably skip to the next paragraph at this point.) For example, (hu)manure is rather stinky.
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People often find it surprising but you usually can't smell it with about an inch of dry plant material such as leaves or grass clippings. Well I mean, *I* can't smell it.
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I could probably reduce the cover material since the grubs drastically reduce odors, but this is a suburban neighborhood with five backyards sharing the wall with this one, so I'd rather not have even a little of that smell wafting about. If I have about 1000 grubs and I use a cover material, will the soldier flies still be able to locate the colony and lay eggs?

Moving in at night; great idea! Been doing that with my not-so-cute-and-little-anymore chickens. Speaking of which, I have got to build them an outdoor coop soon! Nobody's posting in the BioPod forum. What do you think of my current coop grub bin plan? Will this retain enough moisture if it is lined with paper and it has quite a bit of drainage?

I didn't get into the grub collection but I'm thinking PVC pipe cut in half, for one or two ramps along the walls. Fasten with screws. Then a simple closed collection bucket inside the bin. I describe the rest of it on the BioPod forum. http://thebiopod.com/forum/index.php?topic=171.0

Would
you change anything about the coop grub bin plan?

Thanks for all your research and replies!
 

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