I have removed several dead birds from the inducer assemblies of Bryant’s 90% furnaces. They go in through the exhaust pipe. Word of explanation. These furnaces get combustion air and exhaust flue gasses with PVC pipe. There is a disk in the intake that would block them from getting in. They go in and get trapped between the blower wheel and exhaust, where they perish. The bad part is, I cannot cover this under warranty (that’s Bryant’s doing). The birds either cause the inducer to totally freeze, or not run fast enough to activate the pressure switches. Either way… no heat.
When I did repacements, I would occasionally find nests in the flues (PVC, B-vent, masonry). For some reason, birds like to perish inside furnaces and/or flues.