Green’s Dictionary of Slang

chuck-chuck v.

[cry to summon chickens, thus play on chicken (out) v. (1)]

to act in a cowardly manner.

[UK]Mirror of Life 12 Sept. 3/4: [I]t looks fishy when champion-of-the-world scullers want to claim a foul [...] It looks like chuck-chucking it. And, besides, what did be want a fowl for under Hammersmith Bridge? There was no place to cook it.