My muscovy duck's chest seems bigger! Need advice!

[Ninuschka]

Did you dissect the glands?

Yes we did (very gingerly) cut that tennis ball sized gland in half, so that we could better understand the problem (in fact, it was only then that we could confirm that it was an oversized gland). The inside looked just like the outside - same colour and consistency.

 

[Amiga]

Occasionally one of my ducks has had this. In our case it was a temporary imbalance, and corrected itself. There can be different causes. I would look for a vet's help if it is chronic or worsening.