Acording to allmusic.com,
"Out of the three main segments, "Pigs (Three Different Ones)" is the strongest and most flagrant, revealing Waters' deep-rooted liberal views, his distaste for absolute power, and his abhorrence for even the slightest right-wing slant.
Like the album itself, "Pigs" is triple tiered, with each verse pointing a finger at a certain type of fear-laden personality. The first pig that's revealed is the deceitful businessman, the hypocritical and collusive self-proclaimed superior who feels he can cheat and persuade his way to the top. Outlining Waters' revulsion of conservatism and the elite, it's this first stanza that paints a clear picture for the rest of the song and, to some extent, sums up a great part of Animals' conceptual purpose.
In the second verse, Waters gets a little more personal, but in more of a circuitous manner. Here he mentions the "bus stop rat bag" who "radiates cold shafts of broken glass" and is "hot stuff with a hat pin." Although unclear at the time, these references had to do with the up-and-coming political figure Margaret Thatcher, who was at that time a leading member of England's Conservative Party but eventually came into power as Britain's Prime Minister, thus making Waters' deepest fears and premonitions a reality.
The third reference is by far the harshest; a stern lambasting of Mary Whitehouse; a staunch English conservative and meddling advocate for censorship who was a predominant figure throughout the United Kingdom in the mid- and late '70s especially. It's here that Waters' fiercest remarks surface, asking her if she "feels abused" and accusing her of stemming the evil tide while trying to "keep our feelings off the street." Amongst the whole of Animals' symbolisms and enigmatic themes, it is here that Waters is at his most explicit and apparent. The song itself ends up being the most lyrically biting, and Waters' fears about the kind of Britain which was slowly evolving were slowly becoming a reality. "Pigs" may have confirmed his paranoia, but there's no denying that his accounts are discerning and strikingly astute.
With Gilmour's electronic squawk box imitating the haunting sound of a squealing pig, the music throughout "Pigs" becomes instantly trumped by its lyrical content. Uneven, irregular, and phlegmatic, the slow-moving pace and dense tempo is supposed to represent a pig's listless wallow through the mire. Various Hammond organ riffs flow and then recede, and the muddy guitar and bass lines aid in the song's imagery as they latch on to Nick Mason's rather routine drum work. But the music throughout "Pigs" and the rest of Animals is justifiably secondary in this case, and those who favored Pink Floyd's musical adeptness and the uniformity of the band as a whole were understandably disappointed with the final result of Animals when it reached the shelves. But for those who longed to hear Waters bear his feelings, exclaim his conservative hatred, and expose himself as an even angrier young man were, of course, in their glory." — Mike DeGagne
http://www.allmusic.com/cg/amg.dll?p...3&sql=X1831106
Does everyone here agree with this? Are these individuals really the 3 "pigs" Roger is talking about?