We have 4 pekin ducks 2 girls(shuggles& jumper)&2 boys ( King& Duke) they are almost 2yrs old. I have never had a problem with them and their eggs. But for the past 2 weeks the eggs are either broke in the nest inside, or the outside nest, or in the kiddie pool we have just for them, the shells are so soft they feel like water balloons. I mix oyster shells in their feed but it don't seen to help- yesterday there was no eggs. If its moulting how long does it last with ducks? is it like with chickens?