And ALL cadaver dogs alert to it. Your point?
I suggest you read this -
These findings are important when considering the use of scent-detection dogs during disaster victim search and recovery. It is clear that the VOC profile during the early postmortem period is dynamic and changes both hourly and daily. Notably, the period on day 2 whereby the VOC profile transitioned to a complex postmortem odour could have potential ramifications on the choice of scent-detection dogs deployed to a disaster scene. Given that the early postmortem odour appears to more closely resemble an antemortem odour until day 2, the use of human scent dogs may be more effective during the first 24 h following a mass disaster. While HRD dogs may be more effective as a search tool after 48 h when the VOC profile more closely resembles decomposition odour.
The pig didn't enter the antemortem stage until 2 days after death, so are you saying Madeleine was in 5a for two days? There is no gas emitted in the early stages of decomposition, so there was no death scent wafting around in corners in 5a.