A couple of days ago I noticed that one of the ducks was limping and falling every few steps.  Yesterday it collapsed outside the kitchen door but then managed to get up and follow the other ducks as they made their way around the muddy puddles.  Later on we couldn’t find the limping duck (I think it is a drake as it rarely quacks) but it turned up at the back of the polytunnel in the afternoon and we picked it up and put it on its own in one of the spare poultry houses.  This morning I let all the ducks into the run but won’t be letting them out into the garden and fields so that “limper” isn’t tempted to walk too far.