As crazy as it sounds this might be it. My only experience is with my lone wood duck. Who was already on ground when she was rescued. I know that they have a hard time eating initially as chicks, and is what I thought of after reading this. But if their intake is being monitored than that can be ruled out. I'm going to have to look into this dropping thing when I get home tonight. I know that wood ducks can drop from a pretty epic hieght, I was unaware of the mandarins. Was the egg layed or purchased? If your going to let a hen brood it just put the brooder up several feet and don't use a ramp. I'm planning on building a tree house for qbert my wood duck when I did her some mates. I'm going to look up this whole dropping thing when I get home.