Animals & Housing
The study was conducted at the open-air farm Ängavallen in Skåne, Sweden, during the period of June 17 to August 23, 2024. The pigs were housed on a former cropland (~2600 m²) that had not been used by animals for over five years and had previously been cultivated with various crops.
The area was divided into eight pens, each measuring approximately 30 × 10 meters. Each pen contained a wooden hut (3 × 2 × 1.5 m) with straw bedding for resting. On the southern edge of each pen, a water trough was installed and kept filled throughout the day to ensure constant access to water.
Each pen was equipped with a food trough, filled twice daily with ecologically produced oat-based feed from the farm (½ bucket per sow). In addition, raw cow’s milk was provided to both sows and piglets as a dietary supplement.
Sows had full access to their individual pens, allowing them to forage and root freely in the old cropland. Electrical wires divided the pens: one wire was placed at a height allowing piglets to roam freely across pens, while a second wire surrounded the perimeter to keep piglets within the area.
Each sow was housed alone, except in Pen B and Pen D, which were shared by two sows.
I observed eight sows of the breed linderöd pig, with a total of 36 piglets. The piglets were born between the period of 24th of June to 5th of August, while the sows were born between the years 2018 and 2019. Of the 8 sows in the study, only six had litters of their own. All piglets were born on location in the wooden huts within each pen.
Observational Methods
All eight sows and 36 piglets in the six pens were included in the behavioural observations to assess differences in behaviour, elimination location, and substrate preferences. Based on known elimination patterns in pigs, observations were conducted between 09:00 and 15:00, Monday to Friday, for 10 weeks, weather permitting.
Animals were observed on a group sampling basis by walking through each pen and recording behaviours expressed 10–30 seconds before elimination. Imminent eliminations were identified by distinct postural cues in sows and a similar, though subtler, posture in piglets. Each behaviour observed during the pre-elimination window was recorded as a single occurrence, with behaviours defined and listed in the Ethogram below. I also registered the location of each elimination event with a Garmin GPS device (GPSmap 60CSx, Garmin, USA) and recorded if the animal was either defecating or urinating, and if it was a sow or a piglet.
| Behavior type | Behavior | Description |
| State | Stand | The pig remains stationary with all four feet on the ground. |
| Lie | The pig is stationary with most of its body being in contact with the ground. | |
| Walk | The pig moves either forward or backward, including turning, with its head raised. | |
| Event/Duration | Exploration: Sniffing | The pig interacts with its environment by sniffing surrounding objects and substrate at <5 cm away. |
| Exploration: Nosing | The pig presses its snout against an object or substrate, physically touching it for a short duration. | |
| Exploration: Licking | The pig extends its tongue out and touches an object or substrate with it. | |
| Exploration: Rubbing | The pig rubs a part of its body against an object or substrate. Each rub counts as one event. | |
| Exploration: Rooting | The pig uses its snout to push into the substrate repeatedly to actively move it during a longer duration. | |
| Exploration: Foraging | The pig opens its mouth to bite onto an object or substrate, which proceeds into actively chewing on gathered material. | |
| Vocalisation: Low | The pig vocalises with low grunts, either short or long- | |
| Vocalisation: High | The pig vocalises with squeals, screams or loud grunts. | |
| Elimination: Urinating | The pig’s back is crouched, front legs far front, tail curled and lifted over the back. The pig then eliminates through urinating. | |
| Elimination: Defecating | The pig’s back is crouched, hind legs are bent, tail is curled and lifted over the back and is wagged once done. The pig then eliminates through defecating. |
Data Analysis
Statistical analyses were conducted using R (version 4.2.1) via RStudio (version 2022.07.1 + 554). To evaluate differences in behaviours expressed prior to elimination, Chi-square (χ²) tests for independence were used at a significance level of 0.05. Two main hypotheses were tested:
- Differences between animal types:
H₀: No difference in the frequency of a specific behaviour (e.g., sniffing) before a given elimination type between sows and piglets.
H₁: There is a difference. - Differences between elimination types:
H₀: No difference in frequency of a behaviour (e.g., sniffing) before urination vs. defecation within a specific animal group.
H₁: There is a difference.
Mapping illustrations were created in QGIS (version 3.38.3). Each elimination event was displayed with a 10-meter radius of influence, generating heatmaps to visualize density. A colour-coded symbol indicates whether the event was urination or defecation, enabling interpretation of spatial elimination patterns within each pen.
So what did I find exactly? Take a look at the results page if you are interested in finding out!