Earlier today I found one of my older Muscovy drakes looking "off", so I put him in isolation and sure enough he pooped a big pile of green and yellow poop. My drakes normally weigh 12-14 pounds, but would it be safe for me to assume that was his normal weight? He doesn't feel too thin, so what would be a good guess as to current weight? 12 pounds? Well it's a good thing I weighed him, 'cause his actual weight is 8.36 pounds (3.8 kg). Now knowing his weight I can safely medicate him based on an actual weight. 
So for those of you that might end up medicating you bird, please go buy a scale!

So for those of you that might end up medicating you bird, please go buy a scale!