I read this novel when I was young, so it must have been published before the mid 90's. It was about a young boy who discovered a baby dragon on the corpse of its mother who had been hunted by (I think) the boy's brother. I think the boy then tried to take the baby to be reunited with its own kind as dragons were fiercely hunted.
The story was set in a medieval village and I seem to remember the cover being predominantly blue in colour.
The Dragonling by Jackie Koller
Darek can't wait for his first Dragonquest. Then he can be just like his older brother, Clep, the hero who brought down a Great Blue, the largest and fiercest dragon of all. Darek goes to admire the kill -- and finds a dragonling peeking out of the giant dragon's pouch. Scared but curious, he feeds the hungry baby and makes an unlikely friend. But to save the helpless dragonling he must now venture into the fearsome Valley of the Dragons, risking his life to return his friend to his own fire-breathing kind!
Except for the medieval aspect, this could be Robin McKinley's Dragonhaven
Jake lives with his scientist father at the Makepeace Institute of Integrated Dragon Studies in Smokehill National Park. Smokehill is home to about two hundred of the few remaining Draco australiensis, which is extinct in the wild.
....
On Jake’s first overnight solo in the park, he meets a dragon—the thing that he would have said he wanted above everything else in the world. But this dragon is dying—dying next to the human she has killed. Jake knowns this news could destroy Smokehill. The dead man is clearly a poacher who attacked first, but that will be lost in the outcry against dragons. But then Jake notices something even more urgent: the dragon has just given birth, and one of the babies is still alive…
