Bicicleur, according to Wikipedia (
https://fi.wikipedia.org/wiki/Rautakausi), during the Iron Age (from 500 BC ), in Finland, people lived in individual houses or in groups of a few houses. The economy was based on agriculture, hunting and fishing and small scale trade. The cultivated species were barley, spelt, rye, oats and turnip. The plough was a rudimentary hook plough. Domesticated animals were cattle, sheep and pigs. Houses were from 10 to 20 meters long and erected on poles, and the walls were made of intertwined branches or of peat. The amount of Iron Age finds is smaller than that of Corded Ware finds but is enough to show that the Finnish territory was contunuosly populated.
Moreover, the Finnish traditional cow race (itäsuomenkarja) belongs to the rare species of Central Asian steppe cattle that is also found in Volga Ural and even in Yakutia, so the Finnish cow has the same origin as the language.
Reindeer herding is a Saami-specific thing, and it was not practised by Finns who used to live in the warmer areas of the country.
There is not any indication of a new archaeological culture or people arriving to Finland during the Iron Age, and the admixture statistics show that Finns have not mixed extensively during the last 2000 years. However, by the Iron Age, Corded Ware derived groups probably mixed or started to mix extensively with the inland groups to form the modern Finns.