When the farrowing rate is less than 85%, the total returns to estrus are normal (<8%) and the percentage of abortions is also within the normal limit (<2%), the next step is to look at the open sows.
Empty sows are the non-pregnant sows that are serviced again after 60 days post-service.
![](https://www.pig333.com/3tres3_common/dist_nou/css/images/imb5.png)
The percentage of empty sows among serviced sows should always be less than 1%.
Use the blue buttons above or the flow chart to continue your troubleshooting or to access other parts of the tool.
![Types of gestation losses that can lower the farrowing rate, detailing the different types of returns to estrus based on when they occur.](https://www.pig333.com/3tres3_common/art/pig333/16743/empty-sows_169476.jpg?w=820&q=1&ts=1653979446)
Types of gestation losses that can lower the farrowing rate, detailing the different types of returns to estrus based on when they occur.