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Pullets Reared in Conventional Cages -
Live Vaccines

This information is NOT a housing management guide. These sections were created to help explain the relationship between housing and oocyst ingestion. Please consult your veterinarian and bird management guide from the breeding company for housing management information.

Brooding

The brooding and immediate post-brooding periods are important to vaccine success because this is the time where offspring vaccine oocysts can cycle in the barn at low levels. Essentially, the cycling during this phase is acting as an immunity booster to the original vaccine dose; without this cycling, the vaccine will not work as effectively.

General Good Barn Practice Provide chicks with clean, biosecure housing. Ensure that feed and water are readily available to the chicks when they are placed (1). Additionally, proper heat, ventilation and lighting as well as feed and water quality are required for good rearing management (1).

Physical Cage Environment During Brooding: Oocyst Cycling A mesh floor assists in reducing the number of oocysts accessible to the pullet but these mesh floors will not eliminate oocysts from the cage environment. When a live vaccine is used with cage reared pullets, the limited oocyst cycling provided by the mesh floor alone is usually not enough to generate adequate and complete protection against coccidiosis challenge (2). A management method that has been tested is placement of a degradable material (e.g. thick chick paper, fibre trays made of egg carton material) over a portion (40%) of the cage floor that lasts approximately 5 weeks (2,3). A typical Eimeria species will start to shed from the bird between 5 and 7 days post initial ingestion of an infective oocyst (i.e. live vaccine administration). The oocyst takes between 24-48 hours to become infective once shed. The long lasting coverage may provide sufficient duration for low level cycling and thus sufficient exposure to infective oocysts.

chickenconventionalcage

Figure 1. Simple diagram illustrating Eimeria oocyst build-up in a conventional caging system.  A mesh floor (A) will assist in reducing the number of oocysts accessible to the pullet but these mesh floors will not eliminate oocysts.  A tested management method that may provide sufficient duration and exposure to oocysts for low level cycling is the placement of a degradable material (e.g. thick chick paper, fibre trays made of egg carton material) over a portion (40%) of the cage floor that lasts approximately 5 weeks (B).

Chickenconventionalcageexample

Figure 2. An example of the mesh floor without (A) and with (B) 40% cage floor coverage of the conventional cage mesh floor. 

Physical Cage Environment During Brooding: Nipple Drinker Cups If nipple cups are attached to the drinkers this is a potential reservoir for oocysts.

dirtycupincage

Figure 3. Example of a dirty nipple drinker cup for pullets reared in conventional cages.  Be cautious as this dirty cup can be a potential reservoir for oocysts.

General Good Practice for Coccidiosis Management During Rearing

Atmospheric Barn Environment: Get to Know Relative Humidity (RH) - Because barns require ventilation, the outside temperature and humidity can impact the environment of the barn; especially if the equipment does not measure and account for RH of the air feeding the barn.

Example of the minimum outside temperature needed paired with the temperature gradient needed in a generic chicken barn over the first 6 weeks of rearing (1) to achieve an RH of 35% inside the barn (if air handling equipment does not control the RH of the air feeding the barn).

 

 Day 1-2

Day 3-4

Day 5-7

Week 2

Week 3

Week 4

Week 5-6

 RH (%) inside the barn

 35

35

35

35

35

35

35

 Temperature inside barn (°C)

 36

34

32

29

27

24

20

 

Dew point outside barn (°C)

 18

16

15

12

10

8

4

Click HERE to calculate Relative Humidity.

There is not a designated optimal relative humidity percentage set-out for oocyst sporulation but an RH of 35-70% is considered adequate (bird management guides recommend between 60-70%). Interestingly, good monitoring of RH may also help the welfare of the bird (4).

Atmospheric barn environment: Oxygen Access - If the oocyst does not have adequate oxygen access during sporulation, it may not become infective. High ammonia levels resulting from accumulated manure can also kill oocysts.

Physical Cage Environment: Manure Belts - When a manure belt is in use it will rotate and go through a scraping area where manure is scraped off the belt into a manure disposal area. While most of the manure is removed during this process, the scraper cannot remove all of the manure and it is not equipped to remove microscopic organisms, such as Eimeria. In multitier conventional cage system the manure belts act as a roof for the tier level below. When the bird is tall enough they are able to peck at the manure belt roof and potentially at oocysts that remain on the belt (5,6). This issue can act as a potential disease source OR a method to allow for low level of oocyst cycling depending on the number of oocysts being shed and becoming infectious in the environment. 

ManureBeltConventionalCage

Figure 4. Example of a manure belt in use during pullet rearing.  The scraper removes most but not all the manure (A) and is not equipped to remove microscopic organisms, such as Eimeria.  In a multi-tier conventional cage system the manure belt acts as a roof for the tier below (B).  Pullets in lower tiers may have access to Eimeria from the manure belt, especially when they are tall enough to peck at the belt.  (Picture Credits: Guy Kostrey, Sceneskape Productions)

References

1. Anonymous. Layer management guide: Lohmann LSL Classic. In. Lohmann Tierzucht GmBh. 2005.

2. Price, K.R., M.T. Guerin, L. Newman, B.M. Hargis, and J.R. Barta. Examination of a novel practical poultry management method to enhance the effect of live Eimeria vaccination for conventionally housed replacement layer pullets. International Journal of Poultry Science 12:175-184. 2013.

3.Soares, R., T. Cosstick, and E.H. Lee. Control of coccidiosis in caged egg layers: a paper plate vaccination method. J Appl Poult Res 13:360-363. 2004

4. Stamp Dawkins, M., C.A. Donnelly, and T.A. Jones. Chicken welfare is influence more by housing conditions than by stocking density. Nature 427:342-344. 2004.

5.Price, K.R. Use of live vaccines for coccidiosis control in replacement layer pullets. The Journal of Applied Poultry Research 21:679-692. 2012.

6. Dr. Mike Petrik, personal communication.