The Rochdale Pioneers society became highly successful with 1,400 members in 1855 .
The co-op expanded further , after opening additional stores , to have 5,560 members by 1870 .
The Rochdale Pioneers society became highly successful with 1,400 members in 1855 and the co-op expanded further , after opening additional stores , to have 5,560 members by 1870 .