This was extracted from an article on internet which will clarify about KFC coming to and departing from HK during 1970s:
In his book ‘KFC in China: Secret Recipe for Success’, Liu says it was firstly the context in which KFC entered the China market, that paved the way for its eventual success.
Case in point: when KFC first entered Hong Kong in 1973, it quickly grew to 11 restaurants in the following year. But it misjudged the local market and failed to develop a suitable business model. By 1975, all 11 restaurants were forced to close their shutters. Ten years later, KFC came back with a vengeance, eventually franchising its operations to a company called Birdland, which was backed by a group of local investors.