Heated nesting boxes help stop frozen eggs!

Tired of frozen eggs? Learn about Heating your nesting boxes here. Step by step photos included.
By RonP · Nov 10, 2014 · Updated Oct 9, 2015 · ·
  1. RonP
    Last winter was unusually cold for my area, with days turning to weeks of temperatures way below freezing.

    My schedule allowed me to gather my eggs twice a day, 8am and 8pm.

    For weeks I had cracked frozen eggs. Literally dozens of eggs were deemed unfit for human consumption, and fed back the the birds.

    I Quote:
    US FDA says:
    "Shell eggs should not be frozen. If an egg accidentally freezes and the shell cracked during freezing, discard the egg. Keep any uncracked eggs frozen until needed; then thaw in the refrigerator. These can be hard cooked successfully but other uses may be limited. That's because freezing causes the yolk to become thick and syrupy so it will not flow like an unfrozen yolk or blend very well with the egg white or other ingredients."

    My solution was to heat the nesting boxes (3 boxes in total).

    Materials used:

    Seedling heat mats. Each uses 17 watts. Water proof construction. UL listed.
    [​IMG][​IMG] [​IMG] [​IMG] [​IMG][​IMG][​IMG][​IMG][​IMG] [​IMG][​IMG][​IMG]


    I began by cleaning the 16" cube nesting box out completely.
    I cut a 1" hole in the top of the box to insert the power cord of the seed mat.
    [​IMG] [​IMG]
    Then installed mat to box using paint sticks and screws. The mat bends easily when warm.
    [​IMG] [​IMG] [​IMG]
    I covered the mats with the leaf bags, a perfect fit at 16" width. Disposable when soiled.
    [​IMG] [​IMG] [​IMG]
    I covered the leaf bags with shredded junk mail, easily replaced and plentiful, and inserted some ceramic eggs in each box
    [​IMG] [​IMG] [​IMG]
    Connected the 3 boxes to the power cord extension
    Connected the power cord extension to the power strip, which has the thermo cube and LED night light to show when thermo cube is powered on
    The power strip is connected to the light timer, set to turn on at 5:30am, off at 9:00pm. Note that the power to the lights are on the first timer outlet, which first goes through a photocell, so lights only are only on when needed. All power comes from a GFIC outlet. All wiring is inaccessible to the flock.
    [​IMG] [​IMG]


    The light timer supplies power on at 5:30am, off at 9:00pm.
    The Thermo cube powers the mats only when temps reach below 35F, and off at 45F
    The mats heat the nesting material to around 20 degrees above ambient temperatures.

    The "Heated Nest Boxes" help keep the eggs from freezing till temperatures reach around 10F.

    Hope this helps others!


    We had an unusually cold February 2015 for my area, many day temperatures only in the teens.

    My schedule allowed egg collection once around 8AM and once around 8PM.

    My coldest recorded egg temperature was 33F, significantly above the 28F threshold for egg freezing.

    That particular day, daytime high temperatures in the coop were in the low teens (13F), and the eggs were collected at 8:30pm, when ambient temperature was 11F and falling (nighttime lows reached below 0F, unusual for our area).

    The heated nest boxes worked as designed, flawlessly!

    I had 0 frozen eggs, whereas the previous year I had literally dozens...

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Recent User Reviews

  1. sourland
    5/5, 5 out of 5, reviewed Feb 2, 2019
    Excellent and effective solution to a real problem.
  2. spiritpots
    "Great way to keeping eggs from freezing"
    5/5, 5 out of 5, reviewed Jan 21, 2019
    Great idea with good details and photos, too!
  3. JudysMuscovy
    "Unfrozen eggs"
    5/5, 5 out of 5, reviewed Jan 20, 2019
    What a great idea and seems easy enough to do.


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  1. koko365
    Curious.... what is the point of putting ceramic eggs in the nesting boxes?
    1. RonP
      Birds seem to like to lay where others already have. Having eggs (fake) in several boxes helps somewhat to eliminate favorite nest boxes.
  2. blackandtan
    I have to do this! It’s -33 during the day right now and will be -46 tomorrow morning
  3. Farmgirl1878
    What a great idea! Do your girls now spend an inordinate amount of time in the box though? I can imagine it feels pretty toasty when it’s minus thirteen degrees...
  4. Abriana
    Interesting! Good job!

    Also, I LOVE your ceramic eggs! (totally unrelated) They're very colorful and pretty!
  5. RonP
    FYI in case anyone is interested.

    Four years have passed since I built the heated boxes.
    Not one egg has frozen!
    No issues at all with the pads, wiring or thermocube.
  6. RonP
    You can try Outlet Plug Covers, Child Proof Electrical Protector Safety Caps.
      Farmgirl1878 likes this.
  7. Eelantha
    A very interesting tutorial! As soon as I can figure out a way to keep dust off the plugs of my own electrical devices (I'm paranoid over fire accidents), I will try it!
    1. blackandtan
      I think Canadian tire and Home Depot sell weatherproof cord protectors for things like Christmas lights, it’s like a Tupperware that you can slot the cord ends into and shut the lid
  8. jwyles
    Anyone know where I can find faux eggs that look like these for my nesting boxes? I want some!
  9. 3riverschick
    I can do this !I have a seedling mat!
    this would make a warm nest for my hen!
    thank you !
  10. nealj
    Does anyone who does this find any of there hens sleeping in the nesting boxes due to the nicer temps?? Just wondering if that is a problem!!
      Farmgirl1878 likes this.
    1. RonP
      Asked often, the answer is no.
      The birds are just fine in their draft free coop.
      The heated boxes offer little to the birds natural 107F body temperature.
      Farmgirl1878 and aart like this.
  11. N F C
    Very informative, thanks!
  12. AmazingRachel
    Haha, I had the same idea with my seedling growing pads!
  13. Leahs Mom
    I know this is an old article, but If you're still checking on it, I'm wondering if you think that the seedling mats could keep a half-gallon waterer thawed if set on top of one.
    1. RonP
      A half gallon of water is not much.
      The mats are water resistant.
      I would try it!
    2. kklowell
      I made a heated waterer with a 5 gallon bucket and an aquarium heater a couple of months ago and haven't had any issues with frozen water since, and it has been down to zero F here. I used the flat nipples from mypetchicken and they work great.
  14. RonP
    I have done nothing to them all year...using the shredded junk mail, I have never had to change out the leaf bags ...just handfuls of littered junk mail, rarely, tossed into the outdoor deep litter run.
    We did have a freeze spell, this season to date, and they still work flawlessly.
    I don't even think about the eggs freezing anymore...
      cavemanrich likes this.
  15. COChix
    Hi Ron, you still using the seed mats? Wondering how they held up?
  16. RonP
    Year end summation in case anyone actually reads this:
    Automated heated nesting boxes worked flawlessly.

    We had a cold winter for NJ.
    I did not have a single egg freeze, winter season 2014/15!
      cavemanrich and Chlady55 like this.
  17. Brookliner
    I have been very successful keeping my eggs unfrozen using my bantam hen who is broody 365 days a year. She pulls every egg laid into her nest and sits on them until we collect them. It is entertaining watching her collect them. She uses her breast and beak to move the eggs.
  18. RonP

    We have had an unusually cold February for my area, many day temperatures only in the teens.

    My schedule allows egg collection once around 8AM and once around 8PM.

    The heated nest boxes are working as designed, flawlessly!

    This year to date I have had 0 frozen eggs, whereas last year I had literally dozens...

    My coldest recorded egg temperatures was 33F, significantly above the 28F threshold for egg freezing.

    That particular day, daytime high temperatures in the coop were in the low teens, and the eggs were collected at 8:30pm.
      cavemanrich likes this.
  19. RonP
    If it's in the coop, it subjected to dust, period! Wires are not a problem, outlets of course are. All circuits are minimum double GFCI protected, hang vertically, and I dust (leaf blower hanging on coop wall) often enough to minimise and clean any build up.
      cavemanrich likes this.
  20. pdirt
    Ron - very nice write-up. How far away from your chickens do you have all those wires? It looks like a whole lot of wires/outlets/etc...that plenty of chicken dust can get into and potentially short out a wire/outlet and start a fire. But if it's a ways away from your chickens, that would reduce the amount of chicken dust.
  21. Sydney Acres
    Lori Marie, I use seedling heat mats under 2 inches of aspen shavings in my brooder to keep the floor warm for the chicks (see my post above on 12/22/14). I don't put them in a plastic bag, as the mats are already plastic or rubber, and they get wet when I use them for seed germination without problems. I also use them under some 3/4 inch soft foam tiles (like stall mats, but soft), then covered by one inch of aspen shaving in my geriatric chickens house. They've never gotten too warm, but they're always covered by more than an inch of material.
  22. ellend
    Re: cracked eggs: Bacteria are microscopic, and very plentiful even on completely clean-looking, fresh eggs. If cracked, the ARE contaminated, and bacteria are growing exponentially. Have I ever used them? Yes. Would I feed them to somebody else? No--ESPECIALLY children, elderly, or immune compromised people (certain medications, chemotherapy, known or unknown cancers/leukemias) or pregnant people.
  23. RonP
    Lori Marie, In my trials, the mat does not get all that hot for concern. I have them under dry paper.
      cavemanrich likes this.
  24. Blueline
    RonP; great idea, will need to do this as our eggs do crack in typical winter weather.
  25. Lori Marie
    Would it be safe enough to use one of these seedling mats under the wood shavings to keep my chickens warmer on very cold nights? I would cover it with the trash bags of course then cover with very deep shavings.
  26. GardenDmpls
    The Christmas lights in long vinyl tubes are excellent low heat sources and are on sale this time of year for around four dollars. In our gardening community, they are used instead of seedling mats.
  27. ellend
    Cracked eggs no longer have that protective coating; or ANY protective coating. The area of crack on the shell lets in bacteria. Bacteria grows slower in cold, but still does grow, and chicken coops are not the cleanest of places, even with excellent care. Dust and air currents carry bacteria, even if the eggs look clean.
  28. RonP
    Good luck with that! I have never felt -20F ambient in my area (not counting wind chill factors).
  29. Frosty
    I'm planning to build the roll out nest box and run pipe heating cable through the area where the eggs collect... then see if it will keep them from freezing when it's -20.
  30. RonP
    I found the temperature never too high.
    The box actually helps to insulate the cold out.
  31. dogfish7
    Wonder if mounting the heat mat under the nest box might be better? You wouldn't have to sleeve it with bags and the thickness of the box would stop the temperature from getting too high. Just a thought.
  32. Sydney Acres
    Love this idea. I rarely have an issue with frozen eggs, but I do use my seedling heat mats for the chickens in many ways. My favorite is putting the heatmat on the floor of my brooder, covered by 2 inches of aspen shavings. The floor is never cold, so the chicks move around more and don't huddle under the heatlamp as much. Heatmats are very useful for lots of things
  33. RonP
    Cracked eggs compromise the any natural protectant, allowing contaminants such as salmonella an entry point.
  34. scratch'n'peck
    Great idea.
    @nancypo frozen eggs will crack and some of the cracks will be so small we can not see them with the naked eye. That can let in bacteria. But as RonP reported above, if you keep them frozen and thaw in the fridge they should be safe, but the yolk texture will be different.
  35. perchie.girl
  36. RedMeadowFarm
    I have a similar system but with a roll out box design and the eggs resting right on the mat. With -10 temps had no cracked eggs.
      Bogtown Chick likes this.
  37. pernotcortez
  38. nancypo
    And I would think the USFAD probably meant store bought, washed, old eggs on their warning. Fresh eggs (unwashed) have that protective coating on it...
  39. Kscott45
    I just use a heated dog mat under my nest boxes. It's durable, easy to clean and I don't have to worry about a little water getting on it. Just plug in into a temp controlled plug and it goes on and off as needed. There are several different sized mats to choose from.
  40. nancypo
    So not to ask a stupid question- why are cracked eggs unfit for human consumption? Unless they're covered in poo of course. We use a hard wired heat lamp in our coop, and it's been down to 0 degrees (Boise) with no cracker frozen eggs. We use pine shaving which do a great job in the entire coop... Nancy @ LittleHomesteadinBoise
  41. ellend
    I use the Thermocubes also, for a Sweeterheater. I find them quite variable on the temperatures of on and off, and not very reliable in the longevity department, but I haven't found a better solution. The nightlight to show it's working is a very good suggestion (I watch a remote thermometer reading right by my computer) and I'd also suggest to have a spare thermocube, or two, for if this one goes out suddenly. And TEST the ones you buy, right when you buy them. (Make sure they won't turn a lamp on while still warm, then take them outdoors for a while if 32 F or lower, or place them in your freezer for a while, and make sure they WILL turn a lamp on. Likewise, make sure the lamp will go OFF when the cube warms up. I'd purchased brand new "duds." Know that different temp. range thermocubes are available--there is one to turn your fan on and off when the temp gets HIGH, so buy the correct one. (Wish they had one that turned on at 40 deg. instead of freezing...
    Nice post! Thanks!
      cavemanrich likes this.
  42. RonP
    The mats seem to be very durable. Let them "warm up" before bending them. They will bend more easily warmed, as you can see in my pictures. You will just have extra mat going up the back if the box is 12 instead of 16 inches. The bags are for easy, quick cleanups, probably not necessary. Shopping bags will work the same.
      cavemanrich likes this.
  43. Eagleeyeice
    I meant to tell you what a great turorial you posted.
    If I do this, it will be with help from here/you.
    I already have the cube and cookie tin heater, so will just add this.
    My boxes are 12" sq. so I'll have to see if these mats will fit.
    I would imagine that a brown paper shopping bag will work, and protect the mat, and add straw to that.
  44. RonP
    Hello Eagleeyeice,
    The mats are designed to give off heat to increase temps 10-20F. In my installation with 2 bags, (8 layers of paper separation) and additional shredded paper, I consistently see a 19F increase in temperatures. I will rarely see daytime temps in the single digits. As this is sufficient for my needs 95% of my cold season, I have not investigated alternative bedding. As for the question" when the temps are below 10F the eggs freeze" , I have yet to accumulate sufficient data, I am only extrapolating from my existing readings. Hope this helps.
  45. Eagleeyeice
    The "Heated Nest Boxes" help keep the eggs from freezing till temperatures reach around 10F.
    Any idea if you can put straw right on top of the mats? w/no bags
    Are you saying that when the temps are below 10F the eggs freeze?
    right now it's 9F in my coop/4F outside though.
  46. CharMac76
    This is a great idea! I may have to try something similar. It doesn't typically get that cold in my area, but the past week has been freezing!
  47. RonP
    Plug the Thermocube into any standard 15 Amp outlets to provide electrical devices with temperature-regulated operation. This dual-receptacle device will activate when temperatures dip to 35 degrees Fahrenheit and off when it hits 45 degrees Fahrenheit. 120-Volt rating.
    Regulates electricity usage according to temperaturePlastic construction with a beige finishUse with a 15 Amp outletAutomatically turns on at 35 degrees Fahrenheit and off at 45 degrees FahrenheitOffers 2 receptaclesSold in many stores including Home Depot
    Hope this helps.
  48. gclark94560
    More info on the thermo cube please! Where to get, how much?
  49. aart
    Thank Ron....will look forward to seeing some more numbers when your control samples reach freezing and below.

    Thought I was subscribed to this article.......but it's not listed in my subscriptions...sigh
  50. chickwhispers
    That's a really good idea! Love it!

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