Thursday, April 16, 2009

Dead in the Shell

Dying Immediately Before Hatching

After having most hens hatching on the 13th day of incubation, I recently had about a week of roller and border chicks not hatching. while Stafford and Colorbred continued to hatch on the 13th day but not a roller or border would hatch.

Normally, if an fertile egg does not hatch by noon of the 14th day, I check to see if they are alive by floating the egg in a dish of warm water. If the chick is alive the egg will jiggle. Then I move the live eggs to another hen and the eggs will hatch sometimes in a hour or two but certainly by the next morning. This time, however, it did not work, even though I moved them at noon on the 14th day, I just could not get them to hatch.

Every egg that fails to develop or that dies should be necropsied. Early embryonic mortality is common with improper incubation temperature, jarring, inbreeding and chromosomal abnormalities. Deaths at the end of incubation are usually associated with hatching, and the stressful period of switching to pulmonary respiration when the chick must start breathing air. Factors including improper incubation humidity, temperature and turning are leading causes of late embryonic death.

Opening the egg over the air cell, I saw chick after chick dying late in embryonic development, in good position but it had failed to pip through the membrane to breathe air. Its beak was right up against the membrane but it couldn't break it.

Since the transferring of live eggs to other hot hens failed, I had ruled out the hens incubation temperature as the cause for eggs not hatching. When I checked on humidity, I learned that we were experiencing extremely low humidity levels of 19%. And as I compared the roller and border eggs to the Stafford and Colorbred eggs. The shells were much more dense on the Stafford and Colorbred eggs making them resistant to drying out and toughing the membrane as a result of the low humidity! The absence of Spring rains, which are so normal for Kansas, had affected my roller and border hatching. The good news is that we got some rain, now its raining two or three times a week! I simply increased the frequency and amount of egg shell fed to improve the shell, and normal hatching has resumed!

Be sure and read the comment from Shawn Bartlett to this post! Thanks so Much for the Idea!!

Lesson: If something goes wrong do not jump in and change things, two wrongs will not make it right, rather look for the obvious cause and make only minor adjustments as indicated!


Anonymous said...

Howzit Linda,

I dont know if you recall, I also battled with fertile eggs not hatching a two years ago. I did not know what it was, but I think you have again correctly diagnosed. I retrospect I realised that the new bird room I built was much hotter (as I wanted more natural light, I put in three poly carbon roof sheets iso the normal iron corrugated) with the light came unbearable heat. So much so that hens would sit hunched over their nests and breathe open mouthed. Those eggs never hatched, as no doubt they "dried out" too much. When I thought it was the heat, I started to mist the setting hens once or twice a day and therafter the hatching resumed with no further problems! Humidity in the breeding season I have learned is a big deal and just one of many other hurdles to get over. Good luck for the rest of the season, but the misting I can recommend as an additional precaution.


Linda Hogan said...

Howzit Good Buddy:

Thanks so much for the misting idea! Living in Kansas with all those Spring storms including lots of lightening and occasional tornado, I have normally waited till the rains started before breeding. This year, the rains are very late and we still have not had a booming thunder storm! I knew the ground was dry and hard but it was a real shock to see that low humidity and sicking to see what happened. I am having a good year over all with over sixty chicks so far and I will breed for at least another six weeks!