Table 1.

Details of layer farms at the time of the first treatment

Farm	Housing	Breed	Birds/Unit	Age (weeks)
01-A	Barn, 2 rooms connected by a not-fully hermetic ceiling	Dekalb white	19,500	40
02-A	Barn with free range, 2 rooms, separated by a wall, connected by a not-fully hermetic door with 2 outdoor areas separated by a fence	ISA Brown	550	63 (C), 54 (T)
06-A	2 rooms, separated by a corridor. Enriched cages	ISA Brown	66,000	40
07-A	1 building, 2 rooms, separated by a corridor. Enriched cages	Novo Brown	62,000	36
09-A	2 separate buildings. Enriched cages	Lohmann Brown	100,000	22 (T), 27 (C)
DC1	2 separate buildings and free-range area	Lohmann brown	2714 (T), 2700 (C)	46
DC2	2 separate buildings. Enriched cages	Hy-Line brown	32,462 (T), 18,851 (C)	58
DC3	2 separate buildings. Enriched cages	Lohmann LSL	54,947 (T), 54,987 (C)	53 (T), 54 (C)

Abbreviations: T treatment group, C control group