I have 5 Pekin duck 6 months old. 2 male 3 female they are laying one egg a day.. I went out yesterday morning and found one of the female in their stall sitting in the nest hole. I thought she had started to brood, I lifted her up but saw no eggs left her food and water. I put her back and went on my way. Checked her last night and still sitting there, picked her up and still no egg. This morning she has moved to the other side of stall. I checked her but found no sign of injury, she did not seem to be in any pain. She will stand but when she tries to walk she falls forward and lays there. Any suggestions.