The film enjoyed a healthy run at Hoyts' drive-ins...
The 'Willard' novel by Stephen Gilbert, originally published as 'Ratman's Notebooks' (68), is an excellent read in the first person.
Was James Herbert's 'The Rats' ('74) inspired by it to any extent? Perhaps. Although 'Ratman's Notes' is not an Animals Attack novel, its subject is still a ripe one for inspiration.
The film sequel to 'Willard' was 'Ben' ('72), which spawned a hit theme song by Michael Jackson, who would probably enjoy the company of four-legged things that squeak.