You’ve probably seen it at the zoo: balls on chains for elephants, bears on a treasure hunt for food, or big cats sniffing marmite. This is environmental enrichment. It provides mental stimulation to captive animals and can prevent stereotypical behaviours linked to poor mental health like elephants swaying or big cats pacing. Public support for enrichment is good enough for San Francisco Zoo to crowd fund a rhino toy.
If we care enough about zoo animals to enrich their environment, why wouldn’t we do the same for farm animals? Pigs and chickens in particular tend to be farmed intensively indoors, either in individual cages or in groups in sheds. Free range farms are less common. How does this affect the welfare of the animals we eat? Do farm animals, like many zoo animals, get bored and express their frustration in stereotyped behaviours? And would they too respond to environmental enrichment?
Farm animals can develop stereotyped behaviours. Horses with stable vices, pigs ‘vacuum’ chewing with empty mouths and chickens feather picking are all problems linked to captive environments that don’t let them express natural or functional behaviour. But farmers and conscientious consumers can change their environment.
Let’s take a closer look at pigs.
If they’re living outside, pigs spend large parts of their day foraging for food, rooting around in plants and earth, and exploring their environment. If they’re indoors on hard floors, there’s no opportunity for them to root around like they can outside. To solve this problem farmers can simulate a more natural environment by providing materials for them to root in. Straw in particular, but also sawdust or mushroom compost, can be an outlet for pigs desire to root and forage.
Objects like rubber hoses, balls on chains or chewable toys can provide a similar experience. German researchers at the University of Kassel have designed a toy for pigs that features three balls on springs. They say it performs better at reducing tail biting than balls hanging from chains. Enrichment toys have an advantage over straw in pig sheds where dung is collected in a slurry system that could be blocked by straw.
Professor Sandra Edwards from the University of Newcastle UK specialises in practical solutions to welfare issues in pigs. She has taken a scientific approach to finding out what type of enrichment interests pigs most, both when it’s first introduced and over longer periods, and how enrichment can reduce stereotyped and aggressive behaviour.
In one study Edwards and her team tested 74 different objects to see how interested pigs were in playing with them over five days. The items ranged from boxes of straw, to ice, mop heads and wind chimes. The top scoring items tended to be edible, have an odour and could be chewed or destroyed. In case you’re wondering, the most popular item was lavender straw with peanuts in a box.
Whether you use straw or objects, enrichment means more work for farmers. Dirty straw needs replacing regularly and enrichment toys have to be kept off the ground and cleaned, because pigs lose interest in them if they’re dirty.
I asked Professor Edwards whether enrichment was a priority for pig welfare, especially in contrast with better-publicised issues like farrowing crates (stalls where sows give birth and suckle piglets which are so small the sows can’t turn around).
Enrichment is a high priority for pig welfare, particularly because it affects the animal on a daily basis for all of its life. Other issues, like farrowing crates, also have welfare significance, but for a smaller window of time. The consequences of lack of functional enrichment can be seen in both chronic and acute behavioural problems like stereotyped behaviours in pregnant sows and injurious tail biting in growing pigs.
— Professor Sandra Edwards
Pregnant sows might be prone to stereotyped behaviours because of their cramped accommodation, for example sows kept in sow stalls are more likely to vacuum chew than sows in pens. Pregnant sows also have a drive to build nests which they can’t satisfy without access to straw or other nesting material. Gestation stalls will be phased out in Australia by 2017, but not farrowing crates.
Tail biting is an aggressive behaviour that’s common in growing pigs or sows kept in groups. It can be such a problem that some farms dock pigs’ tails to prevent it. But a better environment can reduce tail biting. In any case, tail docking is not allowed under enhanced welfare rules like the RSPCA Approved Farming scheme, Humane Choice or organic.
Reducing stress and providing environmental enrichment both stop pigs from being aggressive. Pigs are less stressed if they have enough space and don’t have to compete to access feed.
Environmental enrichment using rootable materials like straw or chewable objects lets pigs express their foraging and rooting behaviours and reduces tail biting. Removing enrichment after pigs have got used to it can lead to bigger problems with tail biting, so it’s important to maintain the enrichment throughout their lives.
Balls on chains aren’t just for elephants at the zoo. Ordinary farm animals like pigs can benefit from environmental enrichment too, and there’s plenty of research to show what interventions make a difference. As a consumer, your choices at the shop can support better pig welfare.
Choosing meat from certification schemes that require environmental enrichment or buying free range means your purchase supports farmers who provide better animal welfare than the legal minimum. It costs farmers to be part of these schemes, so certified products cost more. As consumers, we can reward their investment by choosing to pay for these products.