Table 1. Poultry farm visit schedules in this study

Category	Farm	Race	First sampling		Second sampling		Area
			Visit date	Week	Visit date	Week
Welfare layer	A	Hy-line	18.11.01	14	19.05.10	41	CB
	B	Hy-line	18.11.05	15	19.05.10	42	CN
	C	Hy-line	18.11.09	22	19.05.09	48	GB
	D	Lohmann	18.11.12	17	-	-	GN
	E	Hy-line	18.11.14	18	19.05.09	44	GB
Ordinary layer	F	ISA	18.12.04	44	19.05.16	65	CB
	G	ISA	18.12.06	65	-	-	CB
	H	Hy-line	18.12.11	17	-	-	GB
	I	Hy-line	18.12.12	27	19.05.17	49	GB
	J	Lohmann	18.12.18	66	18.05.16	88	GN
Welfare broiler	K	Cobb	19.03.27	26	19.05.20	29	JB
	L	Cobb	19.03.28	25	19.05.21	32	JB
	M	Cobb	19.04.01	29	19.05.22	JB
	N	Cobb	19.04.01	25	19.05.22	26	JB
	O	Cobb	19.04.02	19.06.04	JB
Ordinary broiler	P	Cobb	19.03.27	25	-	-	JN
	Q	Cobb	19.03.25	-	-	JB
	R	Cobb	19.03.28	25	-	-	JB
	S	Cobb	19.04.01	28	-	-	JB
	T	Cobb	19.04.01	-	-	JB
	U	Cobb	-	-	19.06.03	JB
	V	Cobb	-	-	19.06.03	22	JB
	W	Cobb	-	-	19.06.03	22	JB
	X	Cobb	-	-	19.06.04	23	JB
	Y	Cobb	-	-	19.06.04	25	JB

CB, Chungcheongbuk-do; CN, Chungcheongnam-do; GB, Gyeongsangbuk-do; GN, Gyeongsangnam-do; JB, Jeollabuk-do; JN, Jeollanam-do; Hy-line, Hy-line brown; Lohmann, Lohmann brown; ISA, ISA brown; week, age of the week.