You'd benefit from 3+ more adult (not ducklings or unsexed) females to help take the pressure off of just her. They may be extremely bonded and it sucks to separate them, but not doing so is actually causing her physical harm so you have the make the hard choice. With only one male you can get away with see-through barriers and I'd do that ASAP to give her a break. We're coming up on spring, so it's likely only going to get worse, I'd start looking for new girls immediately so you can get through the quarantine and introduction process ASAP (you'll want to keep the newbies separate from your two for a week or two to be sure theres no illness, and then introduce them to your girl over a period of 'look but dont touch' for anywhere from a few days to a few weeks depending on how they get along, and THEN you add your boy back into the mix)
On the forums page a little bit lower than this one there's a section for buy/sell/adopt and you can also check craigslist and facebook groups, and put the word out at your local feed store as well that you're in the market for some adult females
