I'd heard the term 'Chicken Rock' as early as 1966 or so, heard tell applied by some grumpy Long Island competitor stations to WGBB Freeport. While not a small market -- Long Island was #12 or so nationally -- WGBB was a small station, a class IV 'graveyarder' on 1240. A few of us used to visit them on occasion.
WPLJ programmer Larry Berger said that *he* heard the term when he was at WVOS in the Catskills -- also on 1240.
Though I wanted to be a music DJ and became one, I started out as a news guy at a station in Virginia. And I *did* wind up at WGBB for a spell -- lol, doing NEWS again! The references to the musical genre (of such stations) becoming 'Adult-Contemporary' is spot-on / bullseye. But it has to be noted that many such stations at the time of their initial rise in becoming, say, a substantial #2 niche car button, were also accredited full-service stations, dutifully heavy on news, community bulletin boards and such, jingles, and breezy talk-up DJs an accessibly notch or so subdued from their Top 40 brethren (but whose delivery was still 'modern' enough for an older audience).
1970 or so was when THREE of these developing A/C stations were on the air in the Tampa/St. Pete market. WDAE 1250, WFLA 970 and the more grudgingly-compliant WSUN 620 all could have been called 'chicken rockers'.
As I get it today (after me still being yelled at constantly for being more gauche) the newer term for the original Chicken Rock is now 'Sunshine Pop'.
So, marked by harmonies and friendly 'ba-ba-ba's and many female vocals and the avoidance of hard guitars in favor of gentler (but yet effective) alternate instrimentation, here's a list of some of those initial Chick ..... uh, Sunshine Pop songs for those here who weren't tuned in at the start, in no apparent chronological order :
'Up Up and Away' -- 5th Dimension (perhaps the genre's national anthem at the time)
'Windy' -- The Association
'Will You Be Stayingg After Sunday' -- Peppermint Rainbow
Just about any Pet Clark hit
'Happy' -- either the Sunshine Company or the Blades of Grass
'Talk To Me' -- Sonny and the Sunglows
Many Bacharach and Sergio Mendes compositions
'Can't Find The Time' -- Orpheus
'Sugar Sugar' - The Archies
'Kites Are Fun' -- The Free Design
Anything by the Will-O-Bees (a NYC test group for Mann-Weil songs)
Oddly, quite a few modern songs by MoR crooners (Andy, Sammy, Dean)
Name a Spanky & Our Gang or Mamas & Papas song and you'd be close
'Pretty Ballerina' or 'Walk Away Renee' -- by The Left Banke
And, well, this linked 1969 song. Music to Throw Frisbees Around the Campus To: