Key advice for rodent control on poultry farms

Changes to the law on rodenticide use means farmers have more options to tackle rats effectively. Poultry World talks to BASF rodenticide manager Sharon Hughes.

Poultry World: What are SGARs and how do they differ from other baits?

SH: Second Generation Anticoagulant Rodenticides (SGARs) have been used for rodent control since the 1970s and now provide more than 90% of all current control. They have overtaken warfarin and First Generation Anticoagulants after growing resistance problems.

SGARs fall into two types based upon their potency:

• Single feed baits are highly potent and give both rats and mice a lethal dose from just one feed (about 2g for a rat). No resistance has been found against these.
• Multiple feed baits require rather larger amounts of intake for a lethal dose (about 7g for a rat)

What changes to the law have taken place with regard to rodenticides and baiting, and when did these come into force?

Until January 2015, UK law prevented single feed SGARs being used outside of buildings, effectively confining them to mainly controlling mice which live almost entirely indoors.

See also: Top 10 ways to control rats on farm

But now all SGARs can be used “in and around buildings”. This means bait can be placed as far away as you need to go to control the infestation coming in. Crucially, rats can now be controlled externally, where they spend most time, minimising the number entering buildings where they damage and contaminate stored feed.

All SGARs must be used within a stewardship regime, developed by the Campaign for Responsible Rodenticide Use (CRRU), to manage non-target species risks.

The regime sets out a detailed code of practice for rodenticide use. Most importantly it states only people who hold certificates of competence will be able to buy more than 1.5kg of rodenticides at a time for professional use, from June 2016.

There is, however, a derogation until December 2017 for those in Farm Assurance Schemes with a rodent control requirement. Farm inspectors will expect to see good record keeping of regular rodent monitoring, along with any bait points and amount of bait used.

How do farmers comply with the stewardship regime?

The regime sets out a three-step approach to integrated pest management, as follows:

Exclusion – Eliminate what makes rodents want to live there.

• Clear up feed spillages
• Store grain and feed securely behind closed doors if possible
• Block up obvious rodent access points
• Fit metal strips to the base of gnawed doors
• Keep a clear strip around buildings (free from weeds and clutter) to discourage rats from entering
• Keep hosepipes off the ground so burrows and rat runs are more visible
• Remove any scrap materials from the site
• Dispose of potential nesting materials, such as old insulation or shavings bags

Monitoring – Look closely at your surroundings

• Every month walk round and check for signs of damage or faeces in hot spots, for example feed stores
• Put small patches of sand around the farm on the edges of doorways and on rat runs to assess numbers of footprints and faeces
• If it has been raining, check the mud for signs of rodent activity
• Use a torch to look for pairs of eyes at night
• Use motion sensitive cameras to capture images over night
• Seeing rats in the day indicates a large infestation
• Clear up droppings regularly for accurate assessment of the population

Eradication – A detailed risk assessment should identify if infested areas can be accessed by non-target species, as this influences bait type and positioning. Consider physical, non-chemical controls first.

• When the sheds are empty and the doors are shut, bait heavily indoors to eradicate existing mouse populations
• Killing traps are useful if a small amount of activity has been identified, but will require checking and resetting regularly
• Traps where the rodents remain alive should only be used where non-target species are also present and must be checked daily
• Baiting active rat burrows is the most effective rat control method. By stringing the bait on to a wire, inserting it inside the burrow and securing the wire to the outside of the burrow, it can be easily checked and not dragged in or away
• Plastic bait boxes discourage rats from feeding. Use natural materials (preferably those already on the rat runs) to place bait in, so long as they are covered and protected from non-target species
• Avoid placing bait stations in the open or along the perimeter fences of rural properties, as these are the preferred habitats of field mice and voles
• Place bait boxes in yards close to buildings where non-target species are less likely to forage
• Loose baits must be used with a bait station and are recommended for indoor use only to minimise exposure to non-target species
• Farmers need to understand rodent behaviour for an effective baiting strategy (see Rodent behaviour below)

What about bait selection?

Only use single feed SGARs where necessary, for example if the infestation hasn’t been controlled by a multi-feed or if there is known resistance to the multi-feed bait. Single feed baits are more costly and, as they are highly potent, a more detailed risk assessment is needed.

Only use single feeds outside buildings if they can be adequately secured to safeguard non-target species. And ensure all baits are topped up according to the label. More frequent top-ups and with larger amounts will be required for the multi-feed baits.

Rodent behaviour

• Mice take small amounts of feed from up to 100 places every night whereas rats return to the same place to feed, so a single bait point for a mouse infestation is useless
• Rats are neophobic – they don’t like new things in their environment so will take a while to adjust to a bait box. Natural materials will result in quicker bait uptake
• Mice spend most of their time in the fabric of a building, so use a three-dimensional baiting strategy, not just on ground level
• Rats can become pregnant again from the day they give birth – one breeding pair of rats can increase to a population of 2,000 in 27 weeks
• Mice don’t drink but can use moisture from feed, so an oily seed bait is more attractive

The certification process

There are several options available depending on the farmer’s level of existing knowledge.

Farmers can attend a workshop and sit a test of 20 multiple choice and 10 yes/no answer questions at the end.

A shorter top-up workshop is also available with the same test at the end. For details of the course venues go to rodentcontrolonfarms.co.uk.

Farmers can also complete the full or top-up workshop and test online at www.farmecademy.co.uk.

Those wishing to just sit the test are advised the read AHDB’s Rodent Control User Guide.

Costs vary between £50 to £150 depending on the route taken and the certificate is valid for life.

Once the farm holding has a certified and registered bait user, anyone may purchase the bait for that user.