All Pigs’ Senses Affect Pig Handling

One of the references cited in the draft Canadian Code of Practice for Pigs1 got me thinking about some video I took several years ago.

The Code’s Appendix K: “Pig Vision & Flight Zone” depicts the flight zone, balance point, and blind spot of a pig2. It came from a paper, ”Pig Vision and Management / Handling”3 whose authors claim that:

–           a pig relies primarily on smell and hearing to situate it in its surroundings and uses sight to complement information gathered by sound and smell whereas humans rely primarily on vision and use sound and smell to complete the information obtained through vision.

–          when humans sense a problem they typically stop and look for the cause whereas a pig will stop and sniff the floor.

The paper emphasizes: ”It is important to keep in mind that the personnel that handle the animals is always playing the role as a threat factor for the animals, this is what gets them to keep moving.”3

The authors recommend that we avoid changes in floor surfaces, strange objects, variable light… that encourage the pig to keep stopping and sniffing, and to move small groups of 5-7 animals so that when some animals do stop you can threaten and excite the ones closest to you enough to get all pigs moving again.

Question: Does the threat of a handler ensure that pigs keep moving?

Situation: We collected video of 48 sows being moved to farrowing. One person released 12 sows at a time in gestation then came long behind them while another person received and penned sows in the farrowing room. We had one of the cameras mounted on the farrowing room door pointed towards gestation.

Observations: All sets of 12 sows followed a similar pattern coming down the hallway:

Video 1 Front sows

Each group of 12 started with 4-5 sows moving at a brisk walk or trot the full length of the hallway with their heads up, bodies forward with little or no stopping or sniffing. Here the 4th sow slowed to sniff the floor while sows ahead of her entered the room.

A few more sows followed at some distance.

Video 2 Rear sows

Video 2 shows 5 final sows from a group of 12 with the handler behind them. He carried his board broadside and clunked it on the floor occasionally as he walked. Even though this was a relatively low level of threat and no sows balked or refused to move, there was usually at least one sow slowed or stopped and nosing around at any given time. The front sows in this clip picked up the pace as they neared the room, as did the rear sows when the handler stopped to close the gate. Where did sows speed up relative to water and other distractions on the floor? Is this what you would expect.

Why didn’t the first sows in each group of 12 sniff as much as the rear sows that were closest to the handler?

Pigs often try to shift their bodies so they can see pressure – or stop and listen for what they can’t see. Did the body language of sows that were sniffing suggest that their attention was forward or back? Compare them with sows in Video 1.

In his book, “Moving ‘Em”, Burt Smith doesn’t offer a porcine example but does say that many grazing animals can see virtually 3600 around them when their head is down grazing but with their heads raised, the horizontal range is reduced to, in the example of sheep and goats, about 2900.4

Did the sows have their heads down just to sniff?

The reference paper3 tells us that:

–          handlers have to threaten pigs to make them move

–          pigs stop and sniff when they sense a problem ( like maybe the handler moving them?)

–          we need to move small groups so we can threaten pigs enough to keep them moving

Consider these points in light of our videos where sows closest to the handler and most influenced by his presence, noise, and threat spent the most time with their heads down, stopping, and nosing around. Front animals that were nowhere near the handler kept their heads up and kept moving forward.

Can small groups work well?

Yes, if we don’t rely on threat to move them. If the handler had carried his board quietly at his side and followed sows at a comfortable (for the sows) distance without distracting them, they could have moved just as easily as the front sows in each group of 12. He could have pressured any sows  that stopped but then left them alone and let them move.

If the handler had used the same approach as in Video 2 on groups of 5-7 sows instead of 12 it would have taken him twice as many trips. He’d have missed the benefits of front sows moving themselves and had virtually all sows dawdling along to sniff every turd, puddle, and excuse along the hallway. Multiply his extra time by 2 for the fellow waiting in the farrowing room.


The draft Canadian Code of Practice for Pigs limits discussion to pigs’ vision, blind spot, flight zone, and point of balance and disregards what one of their own references says about pigs’ other senses.

Whether moving large groups or small, handlers need to have an accurate understanding of the full range of pigs’ senses and responses.

Use of continuous threat to move pigs is a common cause of pig handling problems.

That’s it for this time.

Take care

Nancy Lidster


  1. Available at:, pp 30-31. Accessed August 9, 2013
  2. Available at:, p 59. Accessed August 9, 2013
  3. Dalmau, A., Llonch, P. & Velarde, A. (2009) What the Experts Say: Pig Vision and

Management/Handling. Available at: Accessed: July 10, 2013.

4. Smith, Burt (1998) Moving’Em. A Guide to Low Stress Animal Handling p44

ISBN 0-9662704-3-6

Tags: , , , ,

4 Responses to “All Pigs’ Senses Affect Pig Handling”

  1. Thanks meant for delivering such wonderful articles.

  2. Hi! I simply would like to give you a big thumbs up for the excellent information you have here on this post. I will be returning to your site for more soon.

  3. Thank you Jannette. I appreciate hearing that people find it useful
    Take care. Nancy

  4. Thank youfor letting me know what you think of it Fredrick.