Drone Daleks are the working Daleks who obey the White Supreme Dalek.
The Drone Dalek was the last Dalek to come out of the Progenitor Machine after the old Daleks used the Doctor's testemony to activate it. The Drone Dalek is red. Then when the Supreme Dalek came out he ordered the old Daleks to be destroyed. The Drone Dalek killed the last Dalek. Then the Drone Dalek and the other Daleks made the lights in London come on when the German bombers were spotted over the channel. Then when Winston Churchill sent three spitfires up to the Dalek Saucer one of them hit the target and the lights went out in the London. However the Supreme Dalek activated Professor Bracewell and told the Doctor it was a bomb. So the Doctor went to Earth and did manage to save Earth. The Daleks however got away.
At the Pandorica the Daleks were part of the Pandorica Alliance who said the Doctor caused the cracks in time. The Daleks and the rest of the Alliance put the Doctor inside the Pandorica. There were three Daleks at the Pandorica and one of them was a Drone Dalek and the other two were an Eternal Dalek and a Supreme Dalek. The other members of the Alliance were Cybermen, Silurians, Sontarans, Judoon and many more.
There may have been a Drone Dalek as one of the Stone Daleks but we don't know if there was one but there might have been.
The Drone Daleks will return in Series 7 in Asylum of the Daleks.
The Drone Daleks have appeared in:
Series 5: Victory of the Daleks, The Pandorica Opens and The Big Bang
Series 7: Asylum of the Daleks