Drowned chick

[chrismahon]

We put 12 Wyandotte eggs into the hatcher, which is a Suro20 (without the rocking cradle) wrapped in extra insulation. The temperature was 37.0C and humidity set to 75%. It took over 24 hours to stabilise the humidity, which I think is an inherent problem with the software controlling the pump?

We had three pip on the morning of day 20 and one hatched almost immediately. In the afternoon we had two more hatch together and all the rest had pipped. 10 minutes later and two more hatched together. At this stage the humidity had risen to 91% and I was only able to bring it down by lifting the lid slightly and putting it back. It took 15 minutes to get the humidity below 80%. Of the remaining eggs one failed to hatch. It had clearly pipped but there was no movement and when I peeled off some shell I could see that the chick was in the correct position but dead.

A local breeder says she has this sometimes. Multiple chicks hatch together and the humidity rises out of control 'drowning' the remainder still in the shells. First time this has happened to us. Anyone else experienced this problem?

 

[dinosaw]

I've had the humidity go that high in similar circumstances in a Brinsea, had 16 hatch, most in fairly short order but a couple of late pippers, nothing you can really do about the humidity with that amount of wet chicks in the incubator, I didn't even raise the lid myself. I would doubt though that it would cause drowning, the amount of moisture that would need to permeate the shell to refill the air space would be huge and the moisture generally forms into water on the lid and then drips down the sides anyway, if anything I have found the increased humidity encourages faster breakout.

 

[chrismahon]

I was thinking along the lines of the chick's lungs filling with fluid Dinosaw, so perhaps drowning isn't the correct term? It had already pipped so was breathing and I can't see any other reason for it dying. All the other chicks were very healthy, produced from eggs from hens free ranging with good food and healthy treats, so no vitamin deficiencies. The air sac was correct and the chick had brought its head out into position ready to break out.

This particular breeder hatches in a Brinsea 390 I think. She produces 2000 chicks a year and buys 2 tons of feed a week. This phenomenon has happened to her several times. I suppose the only way to bring the humidity down quickly in a cabinet would be a mini dehumidifier arrangement.

 

[dinosaw]

I see what you are driving at Chris, took you literally. It's possible I suppose though it doesn't explain why the hatched chicks don't 'drown' or suffocate as well, I reckon it is more likely that the extreme humidity makes it very tiring for the chicks trying to exert themselves during pipping and they run out of energy before they make it out and this effect is greater than benefit gained to softening the membrane from such levels. If you have spent any time around the equator you will know how a RH at 70-80 in 33C heat absolutely saps your energy.

 

[chrismahon]

I think you may be right Dinosaw. All 5 remaining eggs had pipped and were then exposed to very high humidity, but only the weakest died?

We don't need to go to the Equator to experience those temperatures and humidity. We've had 3 weeks over 33C which peaked at 40C (in the shade) with humidity in the high 80's and it was completely exhausting. Now back to a bearable 28 -32C but still no rain since 14th June. The chickens hated it and the Orpingtons suffered terribly.

 

[chickenfan]

Very interesting discussion. It was more humid rather than hotter than normal, but I expect humidity is exhausting for a chick. I read somewhere that more chicks die from high, rather than low humidity. I had a whole lot of chicks hatch at 45 degree humidity a few weeks ago (I forgot which day they were hatching), and they were some of the liveliest I've had after birth.

 

[Marigold]

Yes - I wonder much humidity is encountered by chicks hatching naturally under a broody? Maybe they dry out faster from more contact with the air, rather than being in a closed environment?
I once knew a gamekeeper who hatched chicks using broodies and he reckoned that the hens would get off the nest and go for a walk in long dewy grass early in the morning, returning with damp feathers which kept the eggs moist. Otherwise, how would a broody be able to increase the humidity under her to anything like the levels in an incubator?
Maybe the advice to get the humidity up really high at pipping is actually mistaken in some circumstances? It's generally accepted nowadays that dry, or drier, incubation may be best in the pre- pipping days, so maybe lower humidity throughout is more natural?

 

[chrismahon]

Problem with lower humidity at hatching is the chicks sticking to the membrane Marigold. So I guess the 75% humidity figure is a best hatch rate compromise between stuck chicks by too little and those weakened by too much. I'm wondering if I should aim a little lower next time and set the humidity to 70%?

 

[Marigold]

I thought 70% was the generally accepted level anyway?
Still doesn't account for successful hatches from what must probably be a much lower humidity rate under a broody in a dry nest?
Did I read somewhere that old-style keepers used to put a damp turf under her?

 

[chickenfan]

I have noticed broody hens seem to drink much more when the chicks are about to hatch.

 

[dinosaw]

I would imagine that the humidity level under a broody would be a lot higher than you would initially think. There is very little in the way of air gaps under a broody bird for either moisture or heat to escape. For a (poor) comparison, remember how quickly the old telephone boxes would steam up once you shut the door.

 

[Margaid]

I've read both tales Marigold, about the broody walking through dew soaked grass and nesting on a damp turf. They are both in L Wright's book The Practical Poultry Keeper. He advocates having a nest box with no base, sitting on the ground, and recommends scraping a hollow in the earth before putting in the straw. It was this book that gave me the idea for "droppings board" 3 inches under the perch in my big wooden house.