Infrared heat lamps are gaining in popularity for both pig and chick brooding. Here's a summary of recommendations for heat lamp brooding and some of our observations made on Iowa rural electrification demonstration farms.
Calderwood, David L.
"Using Heat Lamps for Brooding,"
Iowa Farm Science: Vol. 9
, Article 3.
Available at: https://lib.dr.iastate.edu/farmscience/vol9/iss8/3