Every spring my 7 (sometimes 8) ducks all lay normal eggs for about a month, then one of them starts laying soft eggs every day and continues for weeks. All the others lay good hard-shelled eggs, except for a second soft one once in awhile. They all act healthy. This has happened for three years...
I've been keeping a few ducks for three years, for eggs only. I currently have seven. Unfortunately, flock numbers and composition have changed a couple of times because of hawks and minks. I now have five Runners and two Campbells. They forage most of the day and swim in the creek.