The PSU was started in 1981 as a veterinary and technical service provider and it is part of the Ministry of Agriculture Land and Marine Resources (MALMR). In 1981 the staff consisted of three animal health assistants (AHAs) and a veterinarian head of unit, (the only veterinarian willing to work with poultry at that time). The PSU was put in place based on the recommendations from a committee of poultry farmers who had complaints about vaccine efficiency. The PSU was initially run with three AHAs. The unit staff of 1995 consisted of eight AHAs, including two women, who were assigned to different districts in Trinidad. In 1994 the PSU staff made a total of 544 visits to 55 layer farms with a capacity of 477,500 layers and a total production of 3,583,983 dozen eggs (Table 18a). The PSU staff also made 2073 visits to 165 broiler farms with a production of 5,954,710 broilers (Table 18b). Table 18a. Layer farm surveillance 1994 No. farms visited Capacity '000 Total production Total visits Islandwide 55 477.5 3,583,983 544 Source: Annual Report 1994. Animal Health Sub-Division, Ministry of Agriculture, Land and Marine Resources. Table 18b. Broiler farm surveillance 1994 Districts No. farms visited Capacity '000 Total production Total visits St. George 13 165 122 60 Wallerfield 50 162.6 122 60 Caroni 33 557 1871.61 425 Victoria 40 710 2683 1006 St. Patrick 29 408.5 1205.1 557 Total 165 3610.5 5954.71 2073 Source Annual Report 1994. Animal Health Sub-Division, Ministry of Agriculture, Land and Marine Resources. The PSU deals with ducks, guinea fowls and turkeys on a very limited level. The majority of Trinidad and Tobago's chicken farmers are contract farmers who rear broilers in an all-in-all-out system for two large poultry processing plants or five integrators (Warner Grain Mills (WGM), Supermix, Nutrimix, Malabar Farms, Mastermix). These contract farmers have broiler capacities ranging from 5,000 to 90,000. The processing plants supply government institutions, supermarkets and hotels. In 1996 it was estimated that 350,000 chickens were consumed every week. There are also small independent broiler operations that supply live birds to small-scale roadside pluck shops where birds are kept in floor-systems until they are slaughtered and dressed for consumers on demand. There are fewer egg producers than broiler operators in the country. In 1996 it was expected that 2.5 million chicks would hatch from eggs set in August 1996. The chicken industry has been referred to as an assembly-type industry since all the inputs; corn, soya, equipment and the majority of the day-old chicks are imported from the USA. Annual consuption of poultry meat in Trinidad and Tobago in 1994 was 9 kg (24 kg/person) and the number of slaughtered broilers and culled layers was estimated at 16 million in 1995 and 1996 (Lambie et al., 2000). Poultry health is controlled by the PSU. Infectious Bursal Disease is under better control than in the past. Infectious Coryza and Fowl Cholera have been reduced due to better water sanitation. (Brown, 1999b). The PSU recommends Aloe vera for Cocibaccillosis. Coccidiosis has a negative influence on poultry production (Brown, 1999b). The PSU recommends management practices to control Newcastle Disease Virus such as minimising the stress on the immunological system. Salmonella species can influence poultry health, productivity and food safety (Brown, 1999b). Pox and yaws have declined due to better management practices. Vaccines are used for viral diseases such as Mareks, Pox, Gumboro, Avian Reovirus, Avian Cephalomylitis and Infectious Bronchitis. In recent years there has been a resurgence of Gumboro.