They Hatched...And I Learned Something.

Our collection of Cuckcoo Marans and homegrown mutts finished hatching today. It was a long "labor" which started with our first pip early the morning of March 23rd and ended kind of sadly this morning.

As I blogged before, we started out with 12 Cuckcoo Marans shipped from Ohio and 12 eggs from our own chickens. I did a final candling of the eggs on day 18 which gave the questionable eggs a chance to developed into something if they were in fact any good. We had 8 of our own eggs and 9 of the Marans eggs that definitely had growing, moving chicks in them.

From day 18 of the incubation to the actual end of the hatch, which is usually around day 21, the most important rule above any is: Do not open the incubator under any circumstances! Humidity plays such a critical role during incubation but even more so during the final days leading to and during the hatch. By opening the incubator during this time you can cause drastic drops in the humidity which endanger the chicks that are yet to hatch. The drier air can quickly wick the moisture out of the eggs' membrane and make them too tough for the chicks to pierce with their beaks and/or literally shrink wrap them in the membrane. Either way they will not be able to hatch and ultimately die in the egg.

Everyone has their "favorite" humidity that they like to incubate their eggs at. They arrive at this magic number through a lot of experimentation and experience. The optimal humidity for the incubator is affected by many environmental factors too such as the altitude, humidity of the house and ventilation rate of the incubator.

Our first hatch in our Hovabator 1588 was very successful and I planned on doing all of the conditions the same on this hatch, too. For days 1-17 the relative humidity was 40-50% and for days 18 to the end of the hatch the range was 60-70%. During the first hatch we had some very short-lived spikes in humidity each time a chick emerged from its egg but this was easily managed by taking the ventilation plug off the incubator for 30 minutes or so to get it back to the desired humidity range.

On this hatch I had no idea that high humidity would be a problem. We had more eggs in the incubator this time and of course more eggs means more chicks hatching. The hatch started very slowly on the 20th day of incubation with a single pip on one of the Marans eggs. This chick hatched and then another later in the evening. It was easy to manage the humidity in the desired range.
There was a point in the middle of this hatch when so many chicks hatched at once that the humidity spiked at nearly 80%. It did not worry me much because I thought low humidity during the hatch was the big danger. I opened the plug on the incubator and it took well over an hour to recover itself back down to 70%. We still had 4 eggs left to hatch 3 of which were pipped by the chicks. One still had not pipped.

The fourth to the last egg to hatch made its way cracking around the egg very slowly and seemed like it could not lift the top of the egg off. It cheeped and cheeped and seemed trapped in the egg even though it had cracked a complete circle all around it. We were perplexed..what was wrong?

I was deathly afraid of opening the incubator (remember the rule!) so we rigged this thick copper wire with a bend in the end of it and ran it through the vent hole in the lid of the incubator to help this chick out of the egg. Luckily we were able to get the egg shell off the little guy's head and scoop the chick out of the egg. The chick was unusually wet and there was about a tablespoon of fluid left in the bottom of the egg. It was also so exhausted from it's ordeal that it was just flopping around and kicking with it's eyes still shut. We thought that it must be deformed somehow. We didn't put two and two together that this chick's egg was so full fluid due to the high humidity that occurred a few hours ago. That was the last egg to hatch on day 21 of incubation.
The next morning the chick that we thought was malformed somehow was just fine walking around and hanging out with his mates. That made us scratch our heads...what was his problem and how did he recover from it? We still had three eggs left: two were pipped and still one was a "no show". The two pipped eggs started to crack and again one of the chicks got stuck in the egg even though it was cracked all the way around. I grabbed my trusty copper wire rescuer and was able to remove the top of the egg from this chick but it was still stuck in the shell. I couldn't get it out without harming it. So, we figured we had one chick that hadn't pip and one that was almost done cracking it's egg, it was worth rescuing this stuck chick. Oh, yes it was one of my Marans chicks, too!

We soaked a washcloth in very warm water, opened the incubator and laid the warm washcloth on the unhatched eggs and removed the egg with the stuck chick. It was just like the other stuck chick, very wet and exhausted to the point you thought it was sick or malformed in some way. We returned it to the incubator and it flopped around for a couple hours before it opened it's eyes and got its legs under it.

The last chick needed assistance hatching also but for just the opposite reason. It was stuck in its membrane because it instantly dried around the chick because we opened the incubator to rescue the wet chick! The wet towel was not enough to keep that egg moist. This chick was like a normal chick though. It had it's eyes open and started walking pretty shortly after hatching.

The final egg never hatched so I performed an "eggtopsy" on it and found a fully developed dead chick in it. This little guy was also a victim of the high humidity that occurred earlier. It was apparent that he had pipped the air cell, which all chicks do before they pip the shell, but was met by a gush of fluid that drowned him. It was a sad ending to an overall successful hatch. We had eight out the Marans and eight out of our eggs hatch.

The folks at the Backyard Chicken Forum were helpful in solving what seemed like a mystery to me. The humidity spike was just too high for too long. But I have leaned from all of this : to be much more careful about letting the humidity rise too high. Some have recommended a range of 60-65%. Also, I think I will go back to hatching just one dozen at a time....for now!