Day 14 – the second candling
December 23, 2013 § Leave a comment
Yesterday afternoon we candled Poppy’s eggs for the second time, this time with Nicola’s assistance. Once again it was not possible or practical to photograph the eggs – as it was, we had to keep Poppy waiting as we went through them all. Being a bit paranoid about the whole humidity thing, I also weighed all the eggs to see if they’re losing weight at the requisite rate. Which was a whole ’nother can of wriggling, worrying, squirmy things …
First, the numbers and comments:
Most of the eggs look beautifully full, although it takes a while to decode what exactly it is that you’re seeing. Which is why the emptiness of egg #7 was actually comforting – very definitely empty, which makes the others, by definition, Eggs with Something Going On Inside Them. (We removed #7 and broke it open – not even any blood vessels. And a bit stinky. Not too bad, but not something to keep hold of.) There were a number of cases where I could see a fluttering movement, which I assume is a heart beating. (Or possibly a chick banging on the egg walls, peeping some variation of “Oi! Turn that light off! I’m trying to get some sleep in here!”) There were still a few which had a bit more emptiness to one side of the embryo than I like, but there’s really nothing I can do about that, other than trust Poppy and keep m
The thing that is a bit worrying is the weight loss. You can measure what the humidity in and around the eggs is like by checking their rate of weight loss. Obviously it’s more of an issue with artificial incubation, but given our issues with Claude, Gabrielle and Olly, it’s something I’m always a bit worried about. In theory the eggs should lose between 11% and 13% by day 18. If the rate is faster you need to increase the humidity. If the rate is slower, you need to decrease the humidity. Again, something you usually only worry about in artificial circumstances, but I thought it would be interesting to check anyhow.
The formula is as follows (where O = original weight, C = weight at candling, D = number of days into the incubation it is when you check this):
% = (((O – C) / O ) / D ) x 18 x 100
or in simpler terms,
- subtract the Candling Weight from the Original Weight
- divide this by the Original Weight (if you multiply this number by 100, you’ll get what percentage of weight loss you’ve had to this point)
- divide this by the Number of Days into incubation you are (which gives you the average amount of weight loss per day to this point)
- multiply this number by 18 (for the amount by day 18)
- multiply this number by 100 to give the estimated percentage.
Yikes. What a mess.
We ended up with projected weight losses of 16.4%, 10.5%, 14.5%, 13.3%, 12.2%, 13.3%, 8.3%, 12.4%, 4.3%, 4.4%, 8.3%, 9.5% and 9.4%* respectively. Which would mean that only eggs # 5 & #8 are progressing properly. (*Egg 13 was added 24 hours later than the others, so is only at Day 13.)
If they were all trending one direction, I would feel reasonably sure that there definitely was something going on, and that I should intervene. But the spread is so wide and so random that I’m not confident that I’m actually seeing anything here, other than noise. For starters, I can’t be certain that I wrote all th weights down correctly – I was rushing, and keeping numbers in my head for a couple of eggs at a time before writing. So it’s quite possible that I muffed some. There there’s the fact that the scales were sitting on the ground, not on a perfectly flat surface. Plus those scales only measure to the nearest 1 gram. And had just (as in that morning) had the battery changed, so was super juiced-up. (Ok, possibly not relevant.) Any one of these things could have had an effect on the measurements. There’s a vague hint of pattern in that Poppy’s eggs seem to be (mostly) not losing enough and Lily’s (mostly) too much, but that’s about it. It certainly doesn’t seem to correspond with my notes about which eggs seemed porous (and which you would therefore expect to lose weight faster).
I think we have to just assume that Poppy knows what she’s doing, and look upon these numbers as interesting, but not (yet) informative. I’ll keep an eye on how they hatch and be ready to dampen membranes if needed.
And if we end up with lots that don’t make it, I’ll kick myself.