59 



of five 360-ml samples three times per week for laboratory bioassay. 

 Therefore, the minimum number of hens used in a treatment group was 10. 



To consolidate manure as much as possible, hens were housed two to 

 a cage in cages measuring 20 by 45 by 43 cm. To prevent cross-contami- 

 nation of manure, two cages were left empty between treatment groups 

 and/or vertical tin dividers ca. 46 cm high were placed in the manure 

 collection area between treatment groups. Manure collection areas were 

 cleaned out before experiments began and covered with sheets of poly- 

 ethylene or tin to catch the treated manure. 



When IGR's were mixed with feed, vertical dividers were placed 

 between feed troughs of treatment groups to prevent hens from sampling 

 treatments other than their own. The continuous watering troughs used 

 by all treatment groups were directly below the feed troughs and cross- 

 contamination was possible via spilled feed. To minimize this problem, 

 clay dividers were placed in the water troughs and water was indepen- 

 dently piped into and drained out of the sections of trough that served 

 each treatment group. 



When IGR's were mixed with drinking water, water troughs were again 

 divided between treatment groups. Water treatments were given to the 

 chickens at 9:00 a.m., 12 noon, and 4:00 p.m. daily in the amounts of 

 50 ml per bird per treatment. Care was taken not to spill treated water 

 into manure collection areas. Water troughs were lined with poly- 

 ethylene to prevent them from being contaminated by unlabeled compounds. 



Feed, treated or untreated, was always offered free choice and 

 water was provided in either a continuous gravity flow system or on the 

 schedule described above. Hens were used instead of roosters so that 

 egg production could be monitored if desired. To maintain a maximum 



