One of the oldest wind farms in US, Altamont pass wind project, is being partly repowered and partly decommissioned. It has 828 Kenetech 100kW turbines with lattice towers, something unimaginable today. The project was controversial because of the number of raptor kills, which is primarily due to the wind farm's location on major migratory route of raptors. Mitigation measures like curtailment during November to February, the high season for birds, were in place. A few turbines were the source of majority of the bird kills, in addition to the high density of the 100kW turbines.
A repowering plan has been proposed which replaces 828 turbines with 27 turbines with rated capacity of 2.1MW.
For more details see this source.