Induced Molting as a Management Tool
	Because of increasing economic pressures, the commercial egg industry must make maximum use of its resources. High interest costs and the need to lower production costs have led many enterprises to use induced molting programs. An induced molt causes all of the hens in a flock to go out of production for a period of time. During this time regression and rejuvenation of the reproductive tract occurs, accompanied by the loss and replacement of feathers. After a molt, the hen's production rate usually peaks slightly below the previous peak rate, and egg quality is improved.
	Molting and Egg Size
	For the egg marketer, induced molting offers a means of matching the egg supply with market conditions. Molted flocks produce a higher proportion of larger eggs than do first-cycle flocks (see Table 1). Periods when high prices or premiums are paid for the larger eggs (usually during the summer) favor molted flocks. Periods when the price spread between medium and large eggs is small (usually in the winter and spring) favor production from pullet flocks. Regardless of the time of year, if flock placements and molting schedules can be adjusted to take advantage of anticipated market conditions, molted flocks can produce greater returns per hen than single-cycle flocks.
	Hen Depreciation
	An even greater benefit of induced molting is that it reduces hen cost per dozen eggs because it lengthens the productive life of the hen. On the average, the cost of a pullet is spread over 20 dozen eggs, and a replacement flock is purchased annually. A molting program allows the pullet cost to be spread over an average of about 31 dozen eggs, and replacement flocks are purchased less often; typically, three times in five years. This difference may reduce egg production cost by more than 4 cents per dozen if pullet costs are high. When pullet prices are low, this savings may fall below 3 cents per dozen.
	Feed Efficiency
	As always, you can't get something for nothing. In the case of induced molting, a major disadvantage is that it leads to poorer feed efficiency. The amount that feed efficiency will drop depends on several factors, including strain, season, equipment and housing type, nutrition, and whether the molting technique is applied properly. If you calculate feed efficiency for a first-cycle flock by including the feed needed to grow a pullet and for the molted flock by including the molt feeds, then you will find that the molted flock will have a better overall feed efficiency. If, however, you calculate feed efficiency from 50 percent production for first-cycle and for molted flocks, you will find that the molted flocks have a poorer feed efficiency.
	Molting from the Producer's Viewpoint
	The decision whether or not to molt seldom rests with the contract egg producer. A successful molting program requires close cooperation between the production and marketing segments of the firm. At no point is this more important than at the laying house. A variety of induced molting methods are used today. Induced Molting of Commercial Layers outlines the most successful molting techniques available. Regardless of the prescribed methods and careful management of the hens and facilities.
	What to Expect from a Molting Program
	When you embark on an induced molting program you should be prepared for a number of changes. The most noticeable effect will be a reduction in the total number of eggs sold. You should expect an average of about 7 percent fewer eggs from molted flocks than from single-cycle flocks. For example, over a five-year period, five single-cycle flocks of 35,000 hens will produce about 3.5 million dozen eggs. Over the same period, three molted flocks of 35,000 hens will produce about 3.27 million dozen eggs, a difference of 230,000 dozen. This difference will obviously result in lower egg income unless specific arrangements are made to offset it. Another noticeable change involves egg quality (see Table 1). A reduction in grade-out is normal and requires the cooperation of the egg packer if the molting program is to be successful. What this means to the producer is that equipment maintenance, adjustment, and operation are even more critical with a molted flock than with a single-cycle flock to insure maximum egg yield. For example, a reduction in Grade A yield of 0.87 percent from a 35,000-hen flock can reduce income by over $280 per year. Thus, little differences can cost money, and daily attention to operating details is very important.
	Table 1. Typical Egg Sizes for Molted and Single-Cycle Flocks Percentage of Eggs Size or Quality Weight (oz. per dozen) Single-Cycle Flocks Molted Flocks Extra large over 27 30 39 Large 24 to 27 41 43 Medium 21 to 24 17 12 Small 18 to 21 8 5 Peewee under 18 4 1 Grade A -- 93 91 Checked and cracked -- 3 4
	A variety of adjustment methods have been used to offset the potential reduction in income. These include providing a cash payment to the producer during the time when the birds are out of production, increasing the contract price for eggs from the second laying cycle or decreasing the penalty for undergrade eggs. To the egg producer, a major advantage of induced molting is the reduction in time that the house is not producing income. Because flocks are replaced less frequently, the laying house will be empty less often, which can help smooth out the egg producer's cash flow. In summary, induced molting offers distinct economic advantages to the commercial egg industry. A molting program must be a team effort to be successful. Before deciding to initiate a molting program, carefully consider all costs and benefits. If your operation, facilities, labor, or management capabilities will not permit you to follow prescribed molting procedures strictly, you should consider other methods of reducing your production  Induced Molting of Commercial Layers Induced molting can be an effective management tool, enabling you to match egg production with demand and reduce bird cost per dozen eggs. Through an induced molt, the productive life of a flock can be extended to an age of 105 weeks. You can adjust the timing of a molt as part of a total profit plan that maximizes egg production over the life span of the hens and matches periods of highest egg production to periods of highest egg prices. The decision to molt a flock should be based on sound management principles and a thorough analysis of your management practices and economic situation. Refer to Induced Molting as a Management Tool, for a detailed discussion of molting program economics. The purpose of an induced molting program is to rejuvenate the reproductive system of the hen. For complete rejuvenation and optimum postmolt performance, the reproductive tract must experience complete regression - that is, egg production must completely stop. Complete regression results in the flock being totally out of production for 14 to 17 days. Because weight loss is closely associated with reproductive tract regression, body weight is closely monitored throughout a molt. The following factors, which are essential to a successful induced molt, are addressed in this guide: Age of the Flock Nutrition Lighting Flock History House and Equipment Design Season of the Year Variations Among Strains The procedures described for a successful six-week molt have been used extensively by the commercial layer industry. Much of the information in this guide is based on practical experience coupled with continuing research. Be sure to follow the recommendations closely. Deviating from the program can produce less than satisfactory results. The age of the flock has a profound influence on the success of an induced molt. Attempts to molt a flock less than 57 weeks old will be hampered by the hen's resistance to ceasing production. Some of the hens will likely not experience an adequate regression and rejuvenation of the reproductive tract. On the other hand, if the flock is more than 67 weeks old, the potential for restoring shell quality is greatly diminished, and the overall economic advantage of an induced molt is considerably reduced. The second laying cycle of the flock should end at 100 to 105 weeks of age. An induced molting program consists of three phases: (1) a premolt period, (2) a period of fasting and weight loss, and (3) a return to production after the fast. Premolt Phase Body Weight Sampling The success of a molt depends on accurate body weight sampling. The premolt weight of the hens is one of the most important pieces of information in the entire program. Do not cut corners in sampling the flock for body weight. One week before withdrawing feed, weigh all the birds in a cage at several locations throughout the house. Select sample cages from all decks, rows, and areas in the house. Mark these cages so that you can weigh the same birds for subsequent body weight samples. Targeting Body Weight Loss The amount of weight loss necessary for complete regression of the reproductive tract depends on the premolt weight of the hens. Table 1 indicates target weight loss for various premolt weight ranges. Many factors affect the method for achieving these goals. Read the fasting and weight-loss section of this guide closely. Table 1. Weight-Loss Targets Premolt Weight (pounds) Target Weight Loss (percent) Up to 3.6 30 3.6 to 3.8 33 Over 3.8 35   Lighting Program To cause the birds to stop laying abruptly, they should be "conditioned" by exposing them to constant light (24 hours per day) for seven days before withdrawing feed. The hens will then experience the maximum decrease in day length at the time of feed withdrawal. Premolt Calcium The addition of supplemental calcium to the feed during the final two days before the feed is removed improves the shell quality of the final eggs laid before production ceases. Adding 100 to 200 pounds of oyster shell per ton in addition to normal ingredients produces the best results. Alternately, oyster shell can be top-dressed in the house at the rate of 5 pounds per hundred hens. Fasting and Body Weight-Loss Phase Monitoring Weight Loss Weight loss must be closely monitored in the fasting phase and compared to the target body weight established in the premolt phase. Weigh all the hens in the same cages as were sampled during the premolt period. Measure body weights on the seventh and ninth day after feed withdrawal, and calculate the average weight loss per day. From this estimated rate of weight loss you can predict when the birds will achieve the target weight loss. Weigh the hens in the sample cages every other day until two cays before they are predicted to reach their target weight loss. Then weigh the sample birds every day. Seasonal Influences on Weight Loss A cool environment causes birds to lose weight more quickly. If weight loss occurs too rapidly, regression of the reproductive tract will not be complete. If a flock achieves the target weight loss before the twelfth day after feed withdrawal, the temperature within the house has been too low. In subsequent molts, steps should be taken to keep the temperature somewhat higher. For the flock that has lost weight too rapidly, begin limited feeding as soon as the target weight loss has occurred. Offer 15 pounds of Molt 1 feed (to be discussed later) per hundred hens per day until the twelfth day after feed withdrawal, at which time full feeding can resume. This procedure will maintain body weight and allow full regression of the reproductive system. Under normal circumstances this limited feeding is not required; it is described here only for situations when weight loss has been too rapid because of low house temperatures (less than 72F) or high air velocities (greater than 500 feet per minute). High house temperatures retard weight loss. If the target weight loss has not occurred by the eighteenth day after feed withdrawal, limited feeding should begin. Offer the birds 10 pounds of Molt 1 feed per hundred hens per day. Continue to monitor weight loss as described above. Housing and Equipment Influences on Weight Loss Many factors related to housing and equipment may cause poor uniformity in body weight. They include temperature differences and other ventilation problems, feed equipment problems, or localized problems with parasites or diseases. It is important to be aware of these factors. Within a house there may be zones that repeatedly produce birds with heavier or lighter weights. For example, hens in cages at different levels may consistently have considerably different weights. In such cases, hens in each cage level can be sampled for weight separately and a target weight loss established for each level. Those hens reaching the target weight loss first may be offered 15 pounds of feed per hundred hens per day to hold their weight constant until all hens have achieved the target weight loss. In other situations where it is not possible to feed the hens of differing weights separately, steps should be taken to eliminate the conditions that produce the nonuniformity. If the weight of birds in the flock is highly variable and an attempt is made to molt them as a single unit, the results may be less than satisfactory. Strain Influences on Weight Loss The North Carolina Layer Performance and Management Tests have shown that the rate of weight loss during a fast varies considerably with strain. Provided that the minimums discussed earlier are considered, strains should be allowed to lose weight at their own relative rate. The rate of weight loss has little or no influence on subsequent performance. Comparisons between strains without regard to these facts are not valid. Livability During Feed Withdrawal Livability should be more than 98 percent through the fasting period. There will be a notable decrease in livability as the flock approaches the target weight loss. Flock History and Livability If the flock has experienced some sort of challenge (such as disease, exposure to mycotoxins, or environmental stress) that has significantly affected egg production or livability in the first cycle, livability during the fasting period may decrease below 98 percent. The extent of the decrease depends on the nature and severity of the challenge and how long the flock has had to recover from the challenge. Before initiating a molt, examine the production records for the flock If there was a notable challenge during the last 8 to 10 weeks of the first cycle of the flock, expect livability during the molt to be lower than normal. If this challenge was severe and very recent, it might be wise not to molt the flock. Lighting Program Appropriate management of the lighting program for the flock is critical during the fasting and weight loss phase. The fundamental requirement is to provide constant or decreasing day length for 21 days after feed withdrawal. The best way to accomplish this depends on the house type and season. The following recommendations for closed housing assume absolute light control. If your house is not completely light tight, use the open housing recommendations. The lighting programs outlined in Table 2 begin on the day of feed withdrawal. In many parts of the United States the natural day length will far exceed the minimum day lengths suggested in Table 2. In midsummer, 30-minute increases in day length on days 21, 24, and 28 will result in extremely long day lengths after the molt. Make certain that the hens experience at least a 15-minute increase in day length on these days. Maximum day length does not need to exceed 16 hours for adequate stimulation. Table 2. Lighting Schedule For Open Houses Days after Feed Withdrawal For Closed Houses (Light Tight) Molts Starting June1-Nov. 30 Molts Starting Dec. 1-May 31 0-20 12 hour 12 hours or natural day length* on day of feed withdrawal, whichever is longer. Use natural day length* on 21st day or 12 hours, whichever is longer. 21 13 hours Increase day length by 30 to 60 minutes to total at least 13 hours. 24 13.5 hours Increase day length by 30 minutes if the increase on Day 21 was less than 60 minutes, to total at least 13.5 hours. 28 14 hours Increase day length by 30 minutes to total at least 14 hours. 35 Resume normal lighting program. Day length should be at least equal to that before the molt, totaling at least 15 hours. *Natural day length begins 30 minutes before sunrise and ends 30 minutes after sunset. Return to Production When the target weight loss has been achieved, the flock must be closely managed as feeding resumes and production begins. Returning the Fasted Flock to Feed Hens that have been fasted must never be returned immediately to full feed. For the first two days offer only 10 pounds of feed per hundred hens to prevent severe crop impaction. After this adjustment period, the hens should be given full feed. Nutrition During the Recovery Period Before the onset of production, the hens must be fed diets that promote rejuvenation of the reproductive tract and maximize feather growth. Two diets are recommended to meet these requirements. The exact formulation of these diets depends on availability of feedstuffs and feed prices. The recommended minimum levels of key nutrients are shown in Table 3. Table 3. Minimum Nutrient Levels of Recovery Diets Nutrient Molt 1 Diet Molt 2 Diet Crude protein 16% 17.5% Metabolizable energy 1,275 kcal/lb 1,300 kcal/lb Total sulfur amino acids 0.65% 0.70% Lysine 0.80% 0.95% Calcium 2.0% 3.75% Available phosphorus 0.4% 0.4% The Molt 1 diet should be fed from the time the flock is returned to feed until egg production reaches the 5 percent level. The Molt 2 diet should be fed from 5 percent to 50 percent production. When 50 percent production is reached the diet should provide daily intakes of 290 kcal of metabolizable energy, 610 mg total sulfur amino acids, 735 mg lysine, 3.8 g calcium, and 400 mg available phosphorus. These levels of nutrients should continue until peak production is reached. The flock should then resume the standard nutritional program used in the first production cycle. Housing Effects The difference in rearing and laying environments between open and closed housing produces fundamental physiological differences in birds. These differences cannot be explained solely by differences in light intensity. High air velocities resulting in "wind chill" contribute to this effect. One result is that flocks in closed housing return to production more slowly after molting than those in open housing. However, there is no corresponding difference in second-cycle productivity. Excellent performance can be attained with either type of housing. Care should be taken not to compare the performance of flocks housed in dramatically different environments without regard for the effects of those environments. Second-Cycle Performance The success of an induced molt is measured by the performance of the flock during the second laying cycle. No exact standards exist for second-cycle production. Field experience and recent North Carolina Layer Performance and Management Tests have produced general goals for molted layer performance. It is most accurate to express second-cycle performance in reference to the first-cycle production of the flock. Generally, molted flocks will lay 60 fewer eggs per hen housed, have a hen-day egg production rate 15 percent lower, and peak 10 percent below first-cycle performance. An example of these differences is presented in Table 4. Table 4. Typical Egg Production Rates for the First & Second Cycle of a Molted Flock Production Parameter First Cycle (20-62 weeks) Second Cycle (63-105 weeks) Eggs per hen housed 222 162 Hen-day production 78% 63% Peak production 90% 80%   Summary Throughout an induced molt it is essential to remember the underlying objective of the process. Maximum regression and rejuvenation of the reproductive tract will occur when the induced molting procedures described in this guide are conscientiously applied. Remember these important steps: Premolting Phase Assure proper body weight sampling. Establish proper body weight loss goal. Begin constant lighting seven days before withdrawing feed. Consider providing supplemental calcium. Fasting and Weight-Loss Phase Monitor weight loss very accurately. Be cognizant of other influences, such as housing and equipment, strain effects, and flock history. Use the proper lighting program. Return to Production Phase Never return birds to full feed immediately. Feed appropriate nutrient levels. Be aware of potential housing effects. Know what to expect during the second cycle.