The Use of Iodine and Chlormadinone Acetate to Suppress Sexual Maturity in Chickens

Previous research reports have shown that a delay in sexual maturity of egg-type pullets was beneficial as measured by improved egg size, improved total egg production or less mortality during the production cycle

Iodine to Suppress Ovulation

Additions of iodine to egg production diets have been used experimentally to delay sexual maturity in pullets. A low energy 14% crude protein grower diet with 0, 2,500, 5,000, and 10,000 ppm iodine added in the form of potassium iodide was fed to replicate pens of pullets on litter and replicate groups of pullets in multiple hen cages. All pullets had been grown under nine hours of light per day from eight weeks until the start of the experimental period, at which time day length was increased to twelve hours. The dietary treatments were started at 17, 18, and 19 weeks of age. All pullets were on treatment for four weeks. They were changed to a 16% crude protein layer diet after the four week treatment period

Cage Density and Hen Laying Performance

What is the optimum density for laying type hens in cages? Over 10 years ago we noted that two hens in an 8-inch cage laid as well as one per cage, and that feed efficiency was superior. Commercial practice of a few years ago was to provide four inches of cage width per bird, thus placing two birds in an 8- inch cage, three in 12 inches, four in 16 inches, etc. Then some poultrymen began using a 3-inch density figure with apparent success. A study was recently completed at this laboratory using 16-inch cages with bird densities of 3, 4, 5 and 6 per cage

Dipping Turkey Eggs Prior to Incubation

Many commercial turkey hatcheries have been dipping eggs in antibiotic solutions prior to incubation in an attempt to control various respiratory infections in young poults. A study was completed this past year with eggs from a breeder flock of a known history of Mycoplasma gallisepticum infection. Eggs were incubated in separate incubators with and without dipping in a solution of 3,000 ppm tylosin tartrate, 2,500 ppm kanamycin sulfate and 1,000 ppm zephiran chloride. Poults of each group were fed to market age on two dietary energy series, one essentially containing an additional 165 Gal of M.E./kg from animal fat additions, with protein levels and all other components remaining constant

Factors Influencing Calcification in the Fowl

Previous studies with turkey poults have often produced erratic results in terms of whether or not there is a need for crude supplements in the glucoseisolated soy diet for obtaining maximum growth and bone calcification. It seemed apparent that some of the differences were due to variation in carry-over of factors influencing calcification from the dam to the poult

Neo-Terramycin and Egg Production

Do modem laying hens need antibiotics for maximum reproductive performance? Although previous reports have shown little or no advantage for their use, there needs to be an occasional check made on this question. Pullets were made available for such a study at the Poultry Research Center this year

Some Effects of Low Protein Grower Diets Fed With or Without Antibiotics on Growth Rate and Subsequent Reproductive Performance

Several studies at this station have shown that Leghorn-type pullets can utilize diets as low as 10 to 12% protein during the growing stage (8 to 20 weeks) without adversely affecting their subsequent reproductive performance. Mortality during the growing and laying period was either unaffected or decreased. However, low protein, low-energy fed pullets tend to consume 1 to 2 pounds more feed during the growing period. As a result, pullet growers have tended to continue using the higher protein and higher energy diets. Two studies have been completed and another is under way to further evaluate low protein grower diets with and without antibiotics on subsequent egg production

Some Effects of Low Protein Grower Diets at Two Energy Levels Fed With and Without Antibiotics on Subsequent Egg Production

Numerous studies, including several at this station, have shown that layer type pullets can tolerate diets as low as 10 to 12% protein during the growing period. In fact, subsequent reproductive performance of pullets reared on such diets has been just as good as that of pullets reared on diets of higher protein content. Other work has shown that use of low energy grower diets, i.e., 1800- 2300 Calories of Metabolizable Energy per kilogram, have produced pullets capable of performing as well or better than those reared on higher energy diets, 2800- 3100 Gal./kilogram. Layer house mortality has generally been lower for pullets grown on the lower energy diets. However, the low energy fed pullets require much more feed, the relative proportions are in inverse relationship to the energy level of the diet. Consequently, pullet growers have generally not used low energy feeds extensively, i.e., oats or barley with hulls or other fiber sources vs. com or milo as the cereal position. This study evaluated two energy levels with and without an antibiotic. Antibiotics have not been shown to be of value for this period of growth on higher energy feeds. But, with low energy feeds, we have little or no information as to their potential value

Sublethal Effects of Mercury on Growth and Reproductive Performance of Layers

Mercury in our environment has been implicated in egg shell thinning and poor hatchability among various species of wild birds. We have used domestic chickens to determine the effect of a range of sublethal levels of two dietary mercury compounds, i.e., inorganic mercuric chloride and organic methylmercuric chloride