I have been watching for signs of being sick. They were all playing in the water then then male suddenly started having a seizure. He has left side weakness and couldn't walk. He had many seizures; I lost count. He eventually stopped seizing after an hour or so. He was very weak after and seemed to still have muscle spasms or something. It's all hard to explain as it was the first time seeing this happen. I looked over their area for a cause. Food was changed (found small amount of mold in food), water tank cleaned again and examined, etc. The runner started showing signs of disorientation Saturday. Went through everything again. Gave the girls secondary water with electrolytes, and the runner a small dose of electrolytes and vitamins orally. I haven't seen symptoms since. Not sure if it was the mold, nutrition deficiency, or something else. They girls do leave their coop and play in the water etc for a bit. They aren't as vocal. When I'm near they just head into the coop and sit. Before they would yell at me nonstop if I was in their area. I'm not sure how reliant ducks are on a male to be around for protection (like my chickens seem to be; they follow the rooster around). I'm afraid to get any more ducks until I'm sure I have the environment under control and they aren't going to die from my lack of knowledge. Do I have to worry about my ducks having heartbreak from the loss of the other? Do ducks care about that kind of thing like some animals do?