Reference: Fataawa Mu’aasirah – Page 251
al-Mowsoo’ah – No.10236
Questioner: After slaughtering the chicken, there still appears to be life in the chicken as it is still moving – so is it permissible to immediately place it in a tank of boiling water, because that helps remove all its feathers? And is this chicken permissible [for us] to eat?
Shaykh: So long as it has been slaughtered, then there is no harm.
Questioner: [Yes], but it still has life in it, and is moving and suffering?
Shaykh: If this is after it has been slaughtered, then there is no harm – it is permissible to eat. However, [while it is in this state] it is not permissible to torture it like this [by placing it in a tank of boiling water].
And Allaah [alone] has the Complete knowledge [of all affairs].