Not for the chickens, but we just installed it on the pony's run-in shed. We did not go with a kit, preferring to buy the pieces separately. With a 50 watt panel, marine battery, inverter and charge controller it was about $500.
Be sure to do all the math first! In particular, look carefully at how much power your fan needs.
I've got a 14" sealed motor fan (granted, probably more than you're going to want for a chicken coop,) and I'm having trouble with it running down the battery. We'll have to add a second panel.
My ideal situation is to end each sunny day with a fully charged battery, which means the panels need to supply enough to run the fan _and_ charge the battery back up for anything that was used after the panels stopped working the previous evening.
To get that to work, I'm going to have to put the fan on a thermostat so that if a storm comes along and cools things off (and blocks out the sun) the fan will turn off.
-Wendy