It’s important for the parent birds to be on a balanced diet, but it is equally important for the environment to be right. It may be that your environment is too dry. Eggs need a certain amount of humidity to be able to hatch. Some hens will get damp and then sit on the eggs. You can google ways to add humidity. Some people attach a jar of water under the nest box. It could also be inexperience on the parent’s part. The first clutch almost always fails, and sometimes the second one does, too. If a pair fails again, it is often a sign that the pair simply isn’t cut out for breeding. It takes a lot of patience to breed birds, and there are no guarantees, even with fertile eggs. I know it is disappointing when fertile eggs fail to hatch, but it isn’t uncommon at all. If you found no signs of the chicks trying to hatch, crack or small hole, then it may be the pair stopped sitting on the eggs too soon. It could also be poor incubation techniques. There are so many factors, it can be hard to narrow down a cause, so adding humidity is a good first step.
Thank you for asking Lafeber,