Duck Eggs

[teresaplus8]

My husband and are new to the poultry scene. We were gifted two ducks by a co-worker (which we are all but positive are males) they are roughly 18 weeks old. We have also acquired two females that are over a year old. We have several questions that we hope can be answered. Right now they are kept separate at night due to inside space, but are together during the day. They other day we noticed one of the females (the one the males pick on the most) running from the males with an egg in her mouth. Unfortunately the egg had been broken and she was actually eating it. We assumed that this was to protect her egg from the males?? Is this common?? Can this be stopped?? What should we do?? We are also wondering about egg fertility. I can not find any conclusive information and this site has always given me good info. How do we know when to start watching for fertilized eggs?? How many do they lay??? How long does she stay fertile??? How long will she lay fertile eggs?? How often do they breed??? Sorry to bombard everyone with all these questions, but trying to learn as much as we can as quickly as we can so we don't do anything wrong. Thanks in advance for any help we can get.