Table 1.

Example demonstrating the application of the flock selection criteria and extraction of mortality chains for back-calculation during the period of interest in four, 10 000 bird flocks with an average normal daily mortality of 0.1% with an HPAI mortality threshold of 0.25%

Day No.a	Flock A mortality		Flock B mortality		Flock C mortality		Flock Db mortality	Flock Eb mortality
	Recorded	Extracted	Recorded	Extracted	Recorded	Extracted	Recorded	Recorded
−6	5		4		2		10	3
−5	3		2		1		9	11
−4	12c	2	9		8		13c	2
−3	17	7	13c	3	7		29d	8
−2	44d	34	35d	25	31c,d	21	32	4
−1	101	91	121	111	39	29	23	33c,d
0	292	282	403	393	65	55	45	34

^aDay 0 refers to the End Day which is also the last recorded data point in the mortality data. The preceding days were negatively numbered in reference to Day 0.

^bThese flocks do not qualify for back-calculation because they violate the inclusion criteria (see text). Mortality in Flock D drops below the mortality threshold on Day −1. For Flock E, there were only 2 days of mortality data above the mortality threshold of 0.25%.

^cStart Day of the mortality chain. It should be 2 or less days prior to the Reference Day and mortality on the Start Day and on the days after must all be greater or equal to the average normal daily mortality 0.1% (10 dead birds per day in this example).

^dReference Day is the first day on which mortality equals or exceeds the set threshold of 0.25% (i.e. 25 dead birds in this example).