Page 14—Poultry Notes Supplement to Lancaster Farming, Saturday Special Report . \ Lancaster Farming —| —l « I SHELL DAMAGE AND MONITORING SHELL WEAKNESS WITH SPECIFIC GRAVITY Dr. Paul H. Patterson Assistant Professor Poultry Science Penn State The actual cost of shell dam age to the egg industry would be a difficult thing to accurately measure, although a recent esti mate made by C. F. Strong and R. W. Bastein, suggest that it could cost the industry $2OO million per year. Shell damage can be encoun tered in a number of places, with the enclosed list clarifying some major causes: 1. Damaged cages or collec tion trays. 2, Excessive bird density in cages. 3. Operation of egg collec tion equipment at speeds which are too fast. 4. Stacking egg flats more than six high. 5. Failure to double the bot tom flat in stacks. 6. Failure to separate over sized eggs in flats. • LAYERS more eggs, improved shell quality • PULLETS achieve body weight goals on less feed • BROILERS improved feed conversion • BREEDERS improve hatchability • TURKEYS better feed conversion 7. Careless handling of eggs on flats or pallets. 8. Failure to remove dead birds before belt collection. 9. Rough areas in floors where forklifts or egg carts travel. 10. Excessive disturbance of birds during peak laying hours, e.g.-manure cleanout, spraying, etc. 11. Failure to carefully main tain and clean egg handling equipment. 12. Failure to properly secure egg containers in trucks. 13. Excessive temperature difference between eggs and wash water. 14. Factors which reduce shell quality such as old hens, heat stress, or improper nutrition. 15. Increased body checks due to crowding in cages or extended day length. A simple thing such as the number of birds per cage can have a dramatic effect on shell quality. Dr. D. A. Roland, Sr. demon strated this quite clearly in a 1978 study (Table 1). f, Sept. 24, 1994 Table 1 Hens/cage Body checks 2 8.3 3 14.9 4 33.8 Eggs gathered between 6 and 7:30 am. One of the best monitoring procedures for measuring shell quality is specific gravity. Research in Table 2 shows that specific gravity of eggs is nega tively correlated with the prob ability that eggs will crack dur ing processing (Holder et al., 1974, Poultry Sci. 58:250). Specific gravity 1.065 1.070 1.075 1.080 1.085 1.090 ILBION® tEPLAMIN® ■QUID To stait a weekly specific gravity testing program, secure a hydrometer that measures the specific gravity of solutions between 1.060 and 1.100. Next get five to nine 5-gallon plastic buckets and add three gallons of water and 3 pounds of salt to each. A dilution of 1 pound of salt to 1 gal of water will give a specific gravity of approxi mately 1.079. Using the hydro meter, add salt or water to each bucket to reach the desired spe cific gravity. An eggshell qual ity score can be assigned to eggs that float in the specific gravity solutions as listed below. Specific Gravity 1.060 1.065 1.070 1.075 1.080 1.085 1.090 1.095 1.100 Place thirty eggs in a wire mesh basket that fits inside the plastic buckets and lower the basket and eggs into the solu tion having the lowest specific gravity. Remove the sinking eggs to the next highest specific Table 2 NT DISTRIBUTORS, INC. P.O. BOX 15 PEACH BOTTOM, PA 17563 PHONE 717-548-3811 Use REPLAMIN® L and POULTRY PA if you want the feathers edge profitability. % cracks 27.3 21.0 11.1 7.5 2.4 0.7 gravity solution and count and record the number of floaters with their specific gravity. Con tinue moving sinking eggs for ward until they float Calculate the percentage of floaters in each solution and calculate the average specific gravity of the entire lot of eggs. For best results, standardize the age and temperature of the eggs you evaluate as well as the temperature of the specific gravity solutions (room temp erature is easiest). A good hydrometer for egg testing should be about 155 mm long with 0.001 divisions from Egg Score 0 (thinnest shell) 8 (thickest shell) 1.060 to at least 1.100. They can be obtained from Fisher Scientific for $lB (cat. no. 11-556 G) at the following address, or by calling (215) 640-7940. Customer Service: Pittsburgh P. O. Box 3029 Malvern, PA 19355 Note: No discrimination is intended and no endorsement by Penn State Cooperative Extension is implied.
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