Qustion 1=The best silent fan would be a computer fan ,They sale one at Best Buy its called a Dynex 4.7" CPU Cooling Fan pushes around 73.7 CFM and the noise level is around 38.5 dba


Qustion 2 = Best way to filter smell is not filter i have had great results with this light and many other have had great results too its an Air purifieing light http://1000bulbs.com/product.php?product=9135


Qustion 3 =Any place that you can hide a cow