I've had several soft shelled eggs (well, my chickens, not me) and haven't seen any cords or anything. The process to form an egg is pretty complex; lots of things can go wrong. There are some threads showing abnormal eggs and it's amazing the weird things that can come out of a hen.It was something I had never seen before. Pretty odd looking. Figured you might have a idea what it might be or what caused it. That is interesting. Thanks. The little BO made a almost full recovery except she will not get back up on the roost with the rest of the birds and never has since she got hurt or went lame. Instead she roost every night on the edge of the nest box on the floor with her head inside the box and her butt outside the box (perfect). She still lays and raises cane (very vocal) She is very small for a BO but high in the pecking order so no problems with getting picked on. Gets along great with RK Broody and the now grown and laying chicks, Honestly never thought she would live, let alone walk again but she made it back.
I wish your little BO could give my stupid EE perching lessons. Monkey, for some unknown reason, has decided she no longer wants to roost and sleeps in a nest instead, which wouldn't be so bad except that she also poops in the nest.
