Officer Message Dragons

Message dragons are a common sight all over the world. Even with new inventions coming out all the time, nothing has been able to surpass the efficiency of the current postal system with the small dragons flying with messages.
Apart from the regular messaging dragons, there is also what is generally known as Officer message dragons. These are used exclusively by the military and are quite unique. They have been selectively bred for centuries to fit this one purpose, with higher intelligence and trainability than regular dragons as well as specific colours.
While regular message dragons are able to go between two places, or go back to one place, officer dragons are trained to go to different places depending on what food you give them as you send them on their way. The recipient hangs that same food in a window, or outside a tent, and thanks to the dragons' keen sense of smell they are able to find their way there. This obviously only works at certain distances, but it means troops can move at regular pace during the day and the dragon will be able to find them later on.
Officer dragons are extremely valuable, and capturing one is often punished with death. They are however very feisty, and usually don't let anyone they don't previously know handle them. Getting acquainted with the Officer dragons is a vital part of the education of higher-ranking officers for this reason.

Oh, finally. I hope you bring good news this time.

Appearance

Like regular message dragons, the officer dragons are small, less than half a metre in length, and very fast fliers.
While regular messagers can be pretty much any colour, officer dragons have a very particular colouring. They are grey on the underside and a dark brown or green on the top. This is to make them more camouflaged as they fly.