Table 1. Distributions of housing type, farm size, and season investigated in 53 broiler farms

	Items	No. of farms	No. of placements
Housing type	Windowless house	26	157
	Open-type house	27	149
Farm size	Small farm	41	242
	Large farm	12	64
Seasons	Spring	53	74
	Summer		83
	Fall		79
	Winter		70
	Total	53	306