While some dinosaurs did have feathers, this trait is believed to be the exception rather than the rule.
The discovery of feather imprints on dinosaur fossils has lead to a lot of speculation over just how many of these prehistoric reptiles would have been adorned with a bird-like plumage. Some scientists believe that most of the dinosaurs would have had them, while others are not so sure.
Personally i don't believe much in these feathers stuff,that is especially for the Large Dinosaurs as Sauropods.And i remember in an interview where the great Sir David Attenborough said,not all Dinosaurs had feathers.Some smaller ones had,the bigger ones like Brontosaurus doesn't have.
I have seen few images of some Sauropods having feathers.I wondered why those artists made it that way,anyway.