Pig slave

Pig slaves were geneticaly-mutated human-pig hybrids. They had a lifespan that measured in terms of weeks. They were both the servants and creations of the Cult of Skaro, following the Cult's emergency temporal shift to New York City in the early 20th century.

History
The pig slaves were humans before the Cult converted them into beasts. They were then used to capture more humans. It is unknown why the Daleks chose pigs, but a possible explanation may be biological similarities between humans and pigs.

When the pig slaves captured humans, the Daleks performed an intelligence scan on each of them. Humans of high intelligence were used for the "Final Experiment", while those of low intelligence were turned into the pig slaves. One individual, Laszlo, was only partially transformed.

The slaves only lived for a few weeks (save Laszlo, as he was not completely transformed). They were amazingly strong, being able to restrain a human with ease. They were also vicious fighters and were trained to slit a human's throat with their bare teeth. They were killed by Martha Jones and Laszlo with electricity from a lightning strike (DW: Daleks in Manhattan/ Evolution of the Daleks). Because historical records of the pig slaves were sketchy and they did not belong to an actual alien race, speculation by the Torchwood Institute seemed to posit that Weevils had been rife in 1930s Manhattan. (WEB: Torchwood website)

Pig slaves were later used on Skaro. (VG: Doctor Who: Worlds in Time)