Good slaughter hygiene and accurate meat inspection in slaughterhouses (SHs) should ensure the hygienic quality of broiler chicken (broiler) carcasses accepted as food and guarantee that broiler meat from the carcasses is safe and fit for human consumption. The purpose of our research was to 1) determine the visible hygienic quality of broiler carcasses by visual inspection, 2) compare the results between the large Finnish SHs, and 3) determine the effectivity of the post-mortem inspection (PMI). We additionally aimed to study whether the requirement to inspect the body cavities of all carcasses during the PMI has had any impact on the visible hygienic quality of broiler carcasses in the SHs. The study was divided into two parts. In study 1, one researcher (the first author) inspected 2200 carcasses after PMI in three SHs and detected that, depending on the SH, 0.7–3.6% of carcasses had faecal contamination, 0.4–2.0% had gastrointestinal (GI) tract parts, 0.1–3.6% had some other form of contamination or other inedible remnants, and 0.2–0.5% showed pathological or organoleptic changes. Study 1 was carried out 2019, before the inspection of the body cavities of all carcasses was in use in PMI in the SHs. One SH had significantly higher prevalences of carcasses with faecal contamination (P < 0.001 &P = 0.002) and residual GI tract parts (P = 0.004 &P = 0.006) than the other two SHs. The visual inspection in study 2 was performed 2020–2022 after the inspection of the external surfaces of all carcass body cavities had been included in PMI or after it was as a part of an own-check system. Only one SH had lower prevalences of carcasses with faecal contamination and residual GI tract parts (P = 0.009 &P = 0.005, respectively) in study 2 than in study 1. In all SHs, faeces were mostly found within the body cavities in both studies highlighting the importance of carcass body cavity inspection. A zero level of faecal contamination was not achieved in any SH. Assessing the visible hygienic quality of carcasses enables to assess the differences between SHs in slaughter hygiene management, enabling the risk categorization of SHs, along with assessing the efficiency of PMI. •Visible faecal contamination was mostly within carcass body cavities.•A zero level of faecal contamination was not achieved in any of the slaughterhouses.•Local inflammation or soiling on carcasses may go unnoticed during post-mortem inspection.•Body cavity inspection is essential to find contamination and remaining visceral parts.•Process hygiene differences between slaughterhouses can be verified by visual carcass inspection.