摘要:
A method of determining the weight of animals and the development of plants in a controlled environment. The method comprises measuring the increase in CO 2 production over a test period. CO 2 production is a measure of the metabolic rate and this is related to weight of animals and development of crops which can often be determined by weight There is illustrated a poultry rearing house (1) having vents (3), lights (6) and an air heater (9). CO 2 sensors (15) are connected to a CO 2 controller (17) and in tum to a central controller (5). To test the increase in CO 2 production over time, the birds are settled into a passive state with no feed and the lights (6) turned off. The level of CO 2 produced is measured. The vents (3) are dosed. After a time, the rate of CO 2 produced is measured and the increase calculated.