weight loss method of egg hatching

Discussion in 'Incubating & Hatching Eggs' started by onthespot, Jul 14, 2008.

  1. onthespot

    onthespot Deluxe Dozens

    Mar 29, 2008
    Riverside/Norco, CA
    I was wondering if anyone here had heard of the weight loss method of egg hatching. I read this on the Files section of a Yahoo Serama group. I guess serama eggs can be very touchy to hatch because of their large surface to mass ratio. (they are small and evaporate easily.) Anyhow, I copy and pasted it here. there are two other files that go with it, but this explains the method. Any ideas, theories about it? One poster was saying she was having problems with some marans eggs not hatching because of the extra pigment inhibiting the evaporation of the eggs and having waterlogged babies hatch that did not live, IF they hatched at alll...

    The Water Loss Method of Egg Hatching

    The Weight-Loss Method and Spreadsheet. Developed by HS Wong and is made available to members of Seramas for use by members only. Please respect my
    intellectual ownership by always mentioning my name as the author
    and Seramas as the group from which you have obtained information on the
    use of the weight-loss method. Questions on the Weight-Loss Method can be posted to me via the Group. I shall try to answer.

    Weight-Loss Method ("WLM")

    1.. A Word About Thermometers
    The right temperature is crucial to hatching success. When I first began
    incubation, in my endeavour to get the "right" temperature, I must have
    bought over 2 dozens thermometers. I have most types available in the
    market - mercury, alcohol, digital to 2 decimal points, digital to one
    decimal point, those dial type with a probe that you stick into the
    incubator, you name it, I bought it. I ordered them from all over,
    from Japan, UK and from the States.

    Most of the thermometers are on the shelf now as I have discovered
    that the kind of thermometer available for incubation use in the market
    is not accurate and that what is important is the thermometer's ability
    to read changes to the temperature accurately, not so much the right
    temperature. Let me explain.

    I have discovered that for each incubator, we must have one or two trial runs
    to arrive at the right temperature as measured by a particular thermometer. Say
    I have a new forced air incubator and a new thermometer. I would set it as
    recommended at say 99.5F. If the trial batch of eggs pips internally at Day 20,
    I will run another batch at say, 99.7F. If the second batch then pips
    internally at Day 18 or Day 19, I will then mark that thermometer and that
    incubator as 99.7F. Thus I will have an incubator which will read 99.5, another
    at 99.6 and yet another 99.9. But if I were to use a scientific thermometer,
    chances are all will be measuring 99.5F.

    B. Introduction to the WLM

    There is very little literature on the Weight-Loss Method. Books generally
    agree that an egg must lose up to 13.5% of its weight optimally. From
    experience, I have found that the range of weight-loss is fairly wide, from
    10.5% to 18%. In this range, if the temperature is right, the embryo will
    hatch. I have found that embryos can withstand too much weight-loss better
    than too little. Eggs losing about 9% and less will have a low rate of
    hatching. Eggs losing up to 25% of their weight have hatched successfully. This
    may account for the reported high rate of hatching using the Dry Method since
    the dry method would cause more weight-loss than otherwise.

    I weigh eggs on the day I set the egg, marking that day as Day 0. I target the
    egg to lose 13.5% of its weight by internal pip ("IP") day, which generally is
    Day 18 or Day 19.

    C. Methods of Weighing

    I have only used two methods. The first method is to weigh each individual egg.
    You do this for expensive or valuable eggs. I do it for serama eggs. I use a
    scale, which can measure up to one decimal point, and I prefer a metric scale.
    Since we are really measuring the weight of an egg against itself, no
    conversion of measurement is required. Thus a metric scale is preferable
    because of the smaller units available. You are keeping track of how many units
    of weight it has loss, so the smaller the units available the better. Some of
    my serama eggs weight a mere 12gms and losses of weight per day can be as
    little as 0.10gms. That's 0.42oz and 0.004oz respectively. A full size chicken
    egg of say, 48gms, losing about 0.36gms per day, is 1.69oz and 0.01oz
    respectively. You can see that to obtain a scale measuring in ounces to that
    accuracy will be expensive.

    The second method that I have used is to measure in groups. I will place 10
    eggs or 20 eggs and then average them out. Example, I will place 10 eggs
    measuring a total of 485.3 gms and work out the weight loss required per day
    which will be 3.6gms, or 17.12oz and 0.13oz respectively. Work based on the
    average for one egg ie, divide the preceding 485.3gms by 10 eggs to arrive at
    the average weight per egg. This way, when you toss out two or three eggs due
    to infertility, you just have to divide the total weight by the number of eggs

    If your scale cannot measure to that accuracy, you can increase the number of
    eggs to 15 or 20 numbers.

    Your scale need not be accurate in absolute terms. What is important is that it
    can measure changes to the weight of the eggs being measured. We are applying
    the same principle as that being applied to the thermometers in my opening
    paragraph. This is a pragmatic solution to the question of costs for small

    Note that the larger the number of eggs you measure at one go, the greater the
    chances of inaccuracies coming in, and the lower the rate of hatching.

    To sum up,

    o The preferred method of weighing eggs is to weigh individually.

    o Metric scales are preferred to imperial scales

    o Weighing eggs by groups or batches is possible but always divide by the
    number of eggs to arrive at the average weight per egg.

    o The larger the number of eggs per batch the greater the chances for error.

    D. Methods of Recording

    There are two methods of recording the data, manual recording or by way of a
    spreadsheet. Using a spreadsheet that I have developed has the added advantage
    that you can "forecast" the weight loss of an egg or a batch of eggs and take
    remedial action days or weeks ahead in a timely manner. Manual recording can
    be tedious and may be alright for the initial learning period. But once you
    are using the method on a regular basis, you really should use the spreadsheet.

    I. Base Data
    The basic data that you will collect to work on is as follows:
    a. weight of egg / batch of eggs on the day you set the egg. I normally write
    on the egg a code for the egg, the date I set the egg, and its weight using a
    pencil. You can also use a permanent marker pen.
    b. The daily or periodic weight of the egg preferably taken at or around the
    time you first weigh the egg on the day you set.

    Using the above data, you work out the following information:
    i. the Required Weight of the egg by Internal Pip Day
    ii. the Required Weight Loss per day
    iii. the Required Weight of the egg every day

    From the above, you can work out a graph showing the Required Weight of the egg
    as the days progresses to Internal Pip day.

    Having established the required or ideal weight loss of the egg, you then
    compare that with the Actual Weight Loss of the egg. From the daily or
    periodic actual weight of the egg, you can determine whether the egg is losing
    too much or too little weight and adjust humidity accordingly.

    Egg No.: A1 (Serama)
    Date Required Weight Notes / workings
    Day 0 12/09/00 18.02 gms * Actual weight on setting
    Day 19 01/10/00 15.59 gms *18.02gms - 13.5%

    Weight Loss Required: 18.02 x 13.5% = 2.43 gms *The egg must lose 2.43gms by
    Day 19
    Est. Weight Loss Per Day:2.43gms/19 = 0.128gms *The egg must lose about
    0.128gms per day

    Day No: Day 7
    Date: 19/09/00
    Actual Wt: 16.43gms
    Notes / Workings
    Required W-L: (18.02 - (7 x 0.128) = 17.12 gms *The egg should weigh
    17.12gms on Day 7
    Required W-L %[​IMG](17.12 - 18.02)/18.02)x100 = - 4.99% *The egg should lose
    4.99% of its weight
    by Day 7
    Actual W-L %[​IMG](16.43 - 18.02)/18.02)x100= - 8.8% *The actual
    loss is 8.8%
    Comments: The difference between the Required and Actual is - 3.88% The
    egg is losing too much weight and humidity must be increased to slow down the

    The above is an illustration of the information you can arrive at from the
    Basic Data you have collected for each egg or each batch of eggs. You don't
    have to use percentages if you do not wish to. From the base data, at any
    point during the incubation process you can determine the progress.
    This type of information is important for serious breeders who may wish to know
    whether a certain hen is laying strong eggs, or whether a new feed is affecting
    egg quality, etc.

    *A note on the Internal Pip Day.
    On Day 18, if your temperature settings are at optimum levels, you will see a
    little dent poking into the air cell. I call this the Initial Internal Pip.
    Normally on Day 19, you will actually see the beak in the air cell. I call
    this the Full Internal Pip Day. I use this day as the target day for the egg
    to arrive at its optimum weight. Thereafter the chick will still lose weight
    but it will not affect its viability.

    I. Sample Data Card or Record
    You can keep a data card or sheet for each egg or batch of egg as follows:
    DATE 03/10/00 DAY 12 W-L NOW + 1.8%. SHOULD BE OK.
    IP DAY 15

    DAY 0 DAY 1 DAY 2 DAY 3 DAY 4 DAY 5
    REQ. WEIGHT 5.98 5.93 5.87 5.82 5.76 5.71
    ACT WEIGHT 5.91 5.85 5.78 5.72 5.68
    DAY LOSS 0.07 0.06 0.07 0.06 0.04
    TEMP 99.7
    HUMIDITY 55%

    This is just a sample.

    Once you are in "control" of each egg or each batch of egg, your breeding
    becomes more "scientific" in the sense that you can now determine the egg
    condition of a particular crossing, or the effects on the egg shell of a new
    feed mixture. You can now take dietary or nutritional remedial action based
    on "facts", ie. if an egg from a particular hen is consistently too porous, you
    can come to the conclusion that its calcium uptake is poor and can specifically
    treat it for the problem rather than blanket treatment of the entire flock.


    The spreadsheet has the added advantage of being portable. I use an out of
    production handheld, the HP200LX. The machine can store years of historical
    data using Lotus 123. Secondhand units are selling for USD299 I believe over
    the internet. I have uploaded a "teaching" spreadsheet at the files section of this group.

    I have also uploaded an FAQ.

    Please respect my intellectual ownership by not erasing the copyright mark
    should you send it to friends or use it.

    Ask me questions to expand on the FAQ and make it more comprehensive.


    HS Wong
    Kuala Lumpur
  2. Haven't heard it before but it makes total sense. I think it's the one thing that many folks don't realize. My eggs lose between 14 and 20% of their weight by hatching. If they don't, there will be some heavy, soggy, dead chicks floating in fluid.

    I use the dry incubation method and have only weighed the eggs a few times just to get an idea of how much they were losing. I just know that when I don't add any water to the bator unless it goes below 30%, I have a better hatch rate. Now I DO increase it to about 70% on day 18...IF I think the eggs are light enough by feel. If not, I may only increase it to 50 - 55%.

    We should probably be concerned about too much humidity rather than too little. JMO...

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