Why would a hen occasionally lay an egg with just the membrane or with a very soft shell? When does the shell form? My husband found this egg this morning, partially covered with a thin shell and part just membrane. It happens occasionally with our 30+ hens.
When I have a problem I try to determine if it is a flock problem or an individual hen problem. I see no reason to treat an entire flock and maybe mess them up if it is one chicken causing the problem. The way I read your post you have a one hen problem, not a flockwide problem. There are a few different things that can cause this. The egg laying process is a fairly complicated process, occasionally a hen can have an oops. If it’s really rare it’s nothing to worry about. We’re all entitled to an oops every now and then as long as we don’t make a habit of it. The general egg laying process is that the yolk is released and starts its way down the hen’s internal egg making factory. Along the way it gets various stuff added. When it gets to the shell gland, some more stuff is added, then the shell material is laid on. After the shell is added, the hen adds brown coloring if it is a brown or green egg. That normally takes about a half hour. Just as it is being laid, a coating we call bloom is added to help keep bacteria out. The entire process takes somewhere around 25 hours. Most of that time is spent in the shell gland, putting the shell material on. This Utube shows the process. How an egg is made utube If a hen is startled or something, she may lay that egg a lot earlier than normal. That’s an oops. Sometimes a hen accidentally releases an extra yolk, two or even more in one day. If they are all released at the same time you can get a double or even a triple yolked egg. I’ve seen doubles but never a triple. If the yolks are released at different times they will travel down that egg making factory separately. A hen normally makes enough shell material to cover one egg a day, not two or three. If all the shell material is used up on the first egg, the second egg can be really thin-shelled or even shell-less. Some hens do that a lot more than others. If it’s pretty rare, it’s an oops. If it happens regularly it is something wrong with the hen causing her to release too many yolks. Some hens just don’t process the calcium they eat to make those egg shells. They may have very high calcium levels in their bloodstream but their bodies just don’t work right to use that for egg shells. It’s often a genetic defect. If it is pretty regular this could be the problem. I don’t know how you are feeding your chickens or where they are getting the calcium for their egg shells. If you are offering a calcium supplement like oyster shells, most hens instinctively know to eat what they need for their egg shells. Some hens’ instincts can be messed up though, although plenty of calcium is available she just doesn’t understand she needs to eat it. Obviously I don’t know what is actually causing that. If it’s fairly rare I would not worry about it. If it’s happening pretty regularly you may have a problem. Good luck figuring it out.
