Don’t let Rodents Nibble Away your Profits

Damage By Rodents

Did you know that a single rat eats as much as 20 to 40 pounds of feed a year? Multiply this by 1000 and you can experience a loss that will impact feed conversion that will affect your bottom line. It has been estimated that rodents can increase poultry feed usage by as much as 2%. When the weather cools, mice and rats move indoors and can wreak havoc on not only feed conversion as well as jeopardize bird health and damage facilities.

Rodents spread diseases to flocks by contaminating feed and bird living area with urine or droppings. Rats and mice do not have bladders, so they continuously urinate and defecate on everything they contact. Rats and mice are linked to poultry diseases such as salmonellosis, colibacillosis, coryza, pasteurellosis, mycoplasmosis, hemorrhagic enteritis, hymenolepiasis, capilariasis and ascaridiasis. Rodents are often vectors that carry over disease organisms from one flock to the next flock. Even if the facilities are cleaned and disinfected, if rodents are present, they jeopardize sanitation efforts by keeping diseases active on a farm due to their ability to harbor pathogens.

Since the upper incisor teeth of rodents continue to grow throughout their life, mice and rats must chew constantly to keep their teeth from becoming too long. This means that insulation, wood, curtains, electrical wiring and even metal objects can be damaged.

Rodent Reproduction and Habits

The most common rodent pests in poultry houses are the house mouse (Mus musculus) and the Norway rat (Rattus norwegicus). Rats mature in four to six months while mice mature in six weeks. Mice produce as many as 8 litters per year with up to six young per litter while rats produce three to seven litters with as many as 18 young per litter. This means that within a year, 42 mice and 16 rats can produce 4,000 rodents!

Mice usually nest within 10 to 30 feet of their food source, but rats will travel miles in search of food. Rodents are typically shy creatures that like dark hiding places. They prefer to travel along walls and stay away from open areas. Mice can crawl through openings the size of a dime and rats can contort their bodies to squeeze through openings the size of a quarter. The Norway rat will burrow under foundations or footings and can dig tunnels up to 48 inches deep with several entrances. Mice can live without a source of water, but rats need about .5-oz. to 1-oz. of water daily. Rodents are nocturnal and prefer to feed at night.

Don’t Give Rodents an Invitation to Stay

Maintain a minimum three-foot space around the outside of poultry barns that is free of brush, trash and weeds. The more bare ground or short grass next to buildings, the less likely rodents will build nests or burrow under footings. Clean up spilled feed near feed bins or feed pans and keep medication rooms tidy and clutter free. Keep unused equipment stored away from production facilities. Keep dead bird disposal area clean and dispose of dead birds on a daily basis. If rodents don’t find the living arrangements attractive, they won’t stay.

Keep Rodents Out and Monitor for Signs of Activity

Prevent access to buildings by plugging holes and sealing doors. Carefully check the perimeter of all buildings for potential entryways and burrows. A common entry point for mice is the unprotected end of corrugated metal siding on buildings. Close openings around augers, pipes and wires with cement or metal collars. Burrows with signs of fresh dirt indicate new rat activity and should be addressed immediately.

Don’t leave rodent monitoring to chance. Develop a schedule for closely checking all facilities and stick to it. Addressing rodents when there are only tell tale signs such as droppings will be much more effective and less costly than waiting until you actually see rodents. It has been estimated that for every rodent, which is actually observed, there are 20 to 50 unseen. This is because of the rodent hierarchical structure. It is young and the old rats that are usually forced to scavenge for food during the day. Therefore seeing rodents during the day means the prime night feeding time is overrun.

In addition to establishing a monitoring schedule, keep records. Knowing where farm rodent havens are and when activity is likely to increase can help a producer to develop an effective control program that prevents infestations.

Maintain Bait and Trapping Stations

Any drastic change to their habitat may cause rodents to abandon a facility. Therefore, when cleaning the exterior of facilities or removing litter, first plan to eliminate the rodent population. Disrupting a rodent nesting area will only encourage them to move to a new location until the changes are no longer threatening.

Rodents are continuously exploring their environment and have a strong dislike for new objects. This makes it important to keep bait stations in the environment continuously. Rodents have poor eyesight and do not see color so adding color to bait is not helpful. In addition, rodents have a keen sense of smell and taste. They can detect even small amounts of toxic chemicals so overdosing baits may only discourage consumption. Rodents can learn to associate tastes with harmful effects of new foods and they can remember this for up to six months. Rodents also prefer fresh foods. Therefore, if a heavy rodent population is suspected, frequent baiting and changing the type of bait may be helpful.

The most common control methods for rodents are poisonous chemicals that are classified as anticoagulants. Anticoagulants disrupt the blood clotting mechanism and cause rodents to slowly bleed to death internally. Most anticoagulant baits must be consumed over several days before enough anticoagulant is built up in the rodent’s system to cause an effect. However, secondgeneration anticoagulant baits can effectively kill rodents with one dose.

Getting the Most From Rodent Baits

Since rodents must consume traditional baits for several days, it is critical that bait stations be kept stocked with fresh bait and that adequate numbers of bait stations are present to supply the whole population. Bait stations are important for presenting poison to rodents because they 1) provide a dark, enclosed environment that attracts rodents, 2) keep bait clean and away from children, pets and livestock and 3) prevent unnecessary loss of bait. Bait stations can be purchased or they can be made out of pvc pipe.

To make a bait station use a 1.5-inch diameter pipe for mice stations or 2.5- to 4-inch diameter pipe for rat stations. Construct a T with a cap for the bottom of the T. Make the base of the T up to 8 to 12 inches long and both sides of the top of the T at least 12 to 18 inches long. Turn it over and attach permanently to side walls along footings.

Table 1 shows the baits available as well as their effects on rodents. Familiarize yourself with the different types of bait and be aware that resistant rodent populations can develop if there are inadequate levels of bait for treating a population or baits are overused. This means that it is just as important to maintain records on what baits are used, as it is to maintain a monitoring schedule. One rodenticide company recommends that baits be switched as often as every two months for second-generation products, but traditional products may be effective for as long as six months.

Conclusion

Rodents can have a detrimental effect on poultry operations because they consume feed, harbor diseases and destroy equipment. Keep facilities clean so rodents don’t want to stay. Monitoring for rodent activity on a set schedule, maintaining adequate bait stations and change baits on a set schedule to head off uncontrollable rodent problems.

Table 1. Commercially Available Rodenticides

Generic Name	Type	Dose	Trade Names
Brodifacoum	Anticoagulant	Single feeding Slow acting death 5-7 days post feeding Rodent continues to feed after lethal dose has been ingested	Attack Talon One Bite Ropax	Havoc Just Jaguar Weather-Blok
Difethialone	Anticoagulant	Single feeding Slow acting death 5-7 days post feeding Rodent continues to feed after lethal dose has been ingested	Generation D-Cease Hombre
Bromadiolone	Anticoagulant	Single feeding Slow acting death 5-7 days post feeding Rodent continues to feed after lethal dose has been ingested	Boothill Maki Trax-one	Hawk Contrac Terminator
Chlorophacinone	Anticoagulant	Multiple feeding Slow acting death 5-7 days post feeding Rodent continues to feed after lethal dose has been ingested	Rozol Rozol-Laq-Berry
Diphacinone (rats only)	Anticoagulant	Multiple feeding Slow acting death 5-7 days post feeding Rodent continues to feed after lethal dose has been ingested	Ramik Green Trap-N-A-Sak Tox II Tomcar Contrax-D	Ditrac Liqua
Warfarin	Anticoagulant	Multiply feedings Slow acting	Ferret Contrax RAX	Final Co-rax
Bromethalin	Metabolic inhibitor	Single feeding	Clout Trounce vengeance	Assault Rampage
Cholecalciferol	Vitamin D	Single-multiple feedings Death 3-5 days post feeding	Quintox
Zinc phosphide	Stomach poison	Single feeding Death immediately	Eraze Ridal-Zinc ZP Squirrel & gopher pellets