Leashed blood tracking dog legislation was signed into law on 6/25/2020 and is legal for the 2020 hunting season. Check with the DNR for the exact regulations as they were not available at the time of this posting.
State Regulations: http://www.iowadnr.com/
Green — Tracking allowed
Red — No Tracking allowed
Gray — Tracking allowed under certain circumstances or in certain areas of the state but not all