I have 2 Muscovy ducklings that are around 7 weeks old I think. We had them out in the yard tonight and we were out there watching the ducks and chickens and I noticed the 2 ducks were in the coop. So I went in and saw one watching over the other one. He was laying on the floor. Appeared to have trouble moving. So we picked him up and got him to water and he still won't get up and move around. He just kind of falls over. He or she can stand so I don't think it is a leg problem. It is panting too. What could this be and what do I do? It had been just fine running around the yard and exploring.