no none of the football fields are heated that would be impossible
NOT IMPOSSIBLE - Invesco Field at Mile High has heating during the winter months by a network of 21 miles of underground hot water tubing.
About 37,813 US NFL football fields.
About 105 (105.876124933827422) US NFL football fields.
About four (3.78129) US NFL football fields.
Not counting the endzones it is 1760 (yards in a mile) x 9 miles / 100 = 158.4 football fields. If you count the endzones you are adding 20 yards to the end of the 100 making it 132 fields.
No all football fields are 100 yards.
53 1/3 yards
like at least 4
About 32 (31.76283748) US NFL fields.