The dogs in this video are both young and not what would be considered a “finished” retriever. To the trained eye there are lots of errors being made here by both the handler and the dog. It will give an idea of what these animals are capable of with some time and effort.
The first dog is 2 1/2 and the second is 3 years. Both these dogs went on to have successful competitive careers.
The idea of “blind” retrieves is that the dog doesn’t know where the destination is. He is expected to take as direct a line as possible and not avoid “factors” such as thick cover and obey the instructions “casts” that the handler gives him. You’ll see how some do better at this than others depending on their level of training. Turn the volume up and you’ll hear some of the discussion around this.
https://youtube.com/watch?v=52t5kmwK6CU&feature=share