Homemade Incubator - Low Humidity

[wolverine]

Hi All,

thanks for all the useful information you guys have posted about incubator design, building and running. We've kept some chickens for a few years, but we've had some bad auction buys recently, and have decided to incubate some eggs.

To that end, I've been reading all your comments and forum posts, which are really excellent, to design and build an incubator. So far I have an incubator:

- Constructed from 18mm MDF, sealed and painted inside and out.
- Lined with 15mm Polystyrene sheet.
- I have two 60w bulbs inside a aviary mesh cage inside the roof, with a 240v PC fan pushing the air around.
- I have a home-made automatic egg turner in the bottom, with a motor on a timer that will turn the eggs every four hours.
- I have a tray of water underneath the egg turner, with some water in.
- I bought a Thermostat from ebay, that controls the temperature. Its an STC-1000, and once you have figured out the wiring, they're AMAZING.

So the temperature is sitting very nicely at 37-38 deg C. It's the humidity I'm struggling with. Our house has fairly high humidity (as it's old and damp!) but as the temperature rises, the humidity falls off, especially if I run the PC fan to keep the temperature even.

1) I have added a tray that sits under the lats of the egg turner. There is plenty of water in this.
2) I have closed up all but one of the vent holes, and temporarily taped up the lid to make sure I am not losing warm moist air.
3) The ventilation hole that feeds the fan is just small, about 8mm dia. and is pretty much the only vent that's open. I have draped a wet towel over the hole to dampen the air coming in.

I'm still struggling to get the relative humidity much higher that 40. Any ideas?

Thanks in advance.

 

[rebel yell]

is it made out of plywood, I dont know the materail you are talking about, how big is the bator ?

 

[Edwards' East of Eden]

Yeah - MDF is the heavy stuff that looks like sawdust glued and pressed into a sheet. Reconstituted plywood.

Kind of like OSB, but think sawdust, not wood chips.

Is your fan blowing across the bulbs? Your fan needs to blow across the bulbs and then directly onto your water source, be it a cloth wicking water up from a bin or a sponge in a bowl or what-have-you. Blow warm air onto dampness, and that will up your humidity. If you try to dampen cool air, then heat it, you'll just heat the moisture back out of the air again.

Make sense?

 

[wolverine]

Thanks, that's helpful.

Yes, MDF (Medium Density Fibreboard). It is just reconstituted sawdust. I have loads of it left over that I was given a few years back, so most stuff I build is made from it! I have a duck house that has lasted two winters made from it (although it's a bit soggy in places.

Thanks for the tips.

When I was researching the design, it would've been really useful to know about the configuration of fan, bulb and water. My fan is in the side, at the top, just under the lid. It blows across two bulbs in a line. (It used to be one bulb, but it blew during testing and the incubator went cold through the night). Below that it the egg turning tray, and below that is the water tray. I could tray and dangle some wicking fabric into the water and attach it to the side opposite the fan and bulbs, I'm just not sure I could do it without my auto-egg-turner getting in the way, but I will have a look.

Thanks for the feedback guys, I will see what I can do!

 

[Edwards' East of Eden]

Yeah - it would have been helpful for me, too! My sponge-in-a-bowl on the other side of the 'bator helps some, but not as much as the paper towel that I've got standing up in a jelly jar of water and thumbtacked to the wall does, which is right in the airflow off the bulbs.

Do you have heatsinks in there? That will help you, too ... if you have sealed water jars or water pillows or whathaveyou, then they hold heat better than air does, so your temperature will hold more steady. Plus, that's that much air that you're displacing that you don't have to keep humid. I used (again) 4oz canning jelly jars, each filled with hot water so the incubator didn't have to bring them up to temperature, and snugged in next to each other holding up my tray.

Nice auto-turner setup you've done!

 

[wolverine]

Thanks, that's very useful.

I'm really pleased with the egg turner - thanks to some advice from here and from YouTube, it works really well! I bought a lot of 1/10rpm motors with integrated gearboxes from eBay and combined one of them with a water timer. It turns the eggs through 1/2 turn over five minutes every four hours.

I'm preparing it to put in some Cream Legbar, Bantam Gold Laced Orpington and Large Fowl Welsummer, so I'm hoping to get it stable.

I'll keep you posted on our results.

 

[wolverine]

Hi

managed to get the temperature stable between 37.1 and 38.0 deg C; and humidty around 43-45%, I hope that will be okay.

Egg turner is working really well, so have added some eggs:

How long should I leave them before candling? The Welsummers are dark-shelled, so will need a while I guess. About a week?

 

[Edwards' East of Eden]

Ever candled before? Up top, in the top of this portion of the forum, there's a sticky thread (it's "stuck" to the top of the page) that has a lot of frequently asked questions and other common references in there - there's a _fabulous_ tutorial on what to look for when candling.

First candle? Sure, look at them, quickly, in about four days - but don't toss anything out unless it stinks to high heaven (and at four days, it won't yet). At ten days, look again - and except for very thick, dark eggs, you'll know. You'll see double dark dots, joined, dancing up and down, and veins. Still, my first go 'round, I kind of acted like they were kids - I didn't throw anything out until it was either 18 or it really stunk.

(just kidding. mostly. 14yo still under review.)

This is my second 'round of actual incubation, with constant study the whole while. I might be a bit obsessive! The first time, I candled them all at 7 days, and made notes on each one in pencil. "8/16 Movement" or "8/16 not sure" or "8/16 clear?", etc. Then, I candled again at 10 and 18 days, making notes again each time. This way I could match my observations over time with actual outcome, and try to fine tune what I was looking for.

This time, I numbered each egg over the aircell and candled at four days. I was pretty sure what was clear and what was not, and I saw one that I was pretty sure was a bloodring. Still, I kept all the eggs - I'm still trying to make sure I know what I'm looking at. Yesterday, at eight days, I candled again, and was sure enough on clears to clear out some, but I held one that might be a bloodring to watch a while longer. My others are dancing fools.

My aircells look a little big to me, and I'm wishing I had weighed each egg before I set them, honestly, and next time I will. It may just be that these are silkies instead of LF, but the aircells look hugely out of proportion to any pictures I've seen before, so I've upped my humidity to try to slow down any more evaporation. These guys would have plenty of room to hatch right now, so I'd rather not concentrate the albumen any more, I think. But, there I go cluttering up your thread with my insecurities - sorry 'bout that.

But - if you're not too far into this, popping them on a scale and pencilling the weight onto them might come in handy later. Eggs are supposed to lose ... 13%? of their weight while incubating. I'm pretty sure that's the number. I'll weigh mine next time, that's for sure.

The land grant college in my state has a Department of Poultry Science, and this is one of the publications they offer online: http://www.poultry.msstate.edu/extension/pdf/hatching_chicks.pdf It's not fancy and glossy and shiny and new, but there's some good information there, including a picture of what your aircell should look like as incubation progresses.

 

[wolverine]

Yes, I think I will need to candle mine shortly. The temperature probe for the thermostat ended up resting on the wood of the egg turner yesterday, which gave a false "low" reading, so the heater clicked on more than it should. When I checked, the thermostat inside was showing 40-41 deg c. It's possible that it was only like that for a few miniutes I guess, but it may have been longer - I'm worried that I've cooked them all...

Will know when I candle them I guess.

Doh!

 

[wolverine]

Hi all,

came home tonight (17:00) to find some eggs had pipped (day 23)

Since then, two Welsummer Large Fowl have hatched (very quickly!) and one Gold Laced Orpington Bantam, which took ages.

We have one where the egg pipped, but the membrane stayed in tact under the shell; it looks a bit bloody. No more movement.