When chickens are slaughtered to meet halal standards, (often for the export market), there are restrictions on the type of stunning. Halal usually requires that the chickens have the capacity to recover from the stun, so Controlled Atmospheric Stunning (gas) may not be acceptable. For this reason, the BCC provides the alternative of effective electrical stunning without live inversion.
As the latter is not yet commercially available, in the interim, a Halal Statement of Intent is available as an alternative version of the BCC for businesses to sign up to.