Behavioral changes of sows with changes in flattening rate

In this study, considering the difficulties for all farms to convert farm styles to animal welfare-based housing, an experiment was performed to observe the changes in the behavior and welfare of sows when the slat floor was changed to a collective breeding ground. Twenty-eight sows used in this study were between the second and fifth parities to minimize the influence of parity. Using a flats floor cover, the flattening rates were treated as 0%, 20%, 30%, 40%, and 50%. Data collection was the behavior of sows visually observed using a camera (e.g., standing, lying, fighting and excessive biting behaviors, and abnormal behaviors) and the animal welfare level measured through field visits. Lying behavior was found to be higher (<italic>p</italic> &lt; 0.01) as the flattening rate increased, and sows lying on the slatted cover also increased as the flattening rate increased (<italic>p</italic> &lt; 0.01). Fighting behavior was higher when the flattening rate was 0% and 20%, and chewing behavior was higher (<italic>p</italic> &lt; 0.05) as the flattening rate increased. The animal welfare level of sows, ‘good feeding’, it was found that all treatment groups for body condition score and water were good at 100 (<italic>p</italic> &lt; 0.05). 'Good housing' was the maximum value in each treatment group was 100, as the percentage of floor increased, the minimum increased from 0% to 78, from 20% to 87, from 30% to 89, from 40% to 94, and from 50% to 96%. The 'good health' was the maximum value of the 0% and 20% treatment groups with the flattening rate was 100, and it was analyzed to be 98 in 30% and 50%, and 99 in 40%. ‘Appropriate behavior’ was the score was significantly lower than that of other items, but when the flattening ratio was 0% and 20%, the maximum and minimum values ​​were 10. At 40% and 50%, the maximum values ​​were 39 and 49, respectively, and the minimum values ​​were analyzed as 19 for both 40% and 50%. These results will be used as basic data about sow welfare for farmers to successfully transition to group housing and flat floors.