How to determine quality eggs by candling method.

Aim: - How to determine quality eggs by candling method. "Candling" is the examination of the internal contents of the eggs using a shielded light in a darkened area. Candling is a way of checking whether 1. They are fertile 2. if fertile, to check the growth and development of the embryo 3. Candling to check air cell size can determine incubator humidity Candling detects bloody whites, blood spots, or meat spots, and enables observation of germ development. During incubation the air sac size should increase as moisture evaporates from the egg. If your humidity levels are about right, the air sac should increase at different days of incubation. White eggs should be tested for fertility on the third day. Brown shelled eggs on the fifth or sixth day because it is difficult to see the embryo clearly before this time. Day 8 onwards is usually when the embryo is more easily identified. 1. Day 3 of incubation (usually pale shelled eggs). 2. Day 5/6 of incubation (usually dark shelled eggs). 3. Between day 8 - 12 of incubation (embryo more easily identified). Negative results: 1) Clear when candled – may be infertile or had a very early death. 2) Embryo with red blood “ring” – early death. 3) Red or black staining – early death. 4) Fertile with red blood vessels. Neutral or Positive results: 1) Dark outline with ill defined detail – possible late death (10 – 16 days) Give them a little more time though. 2) Live embryo with bill in air sack – due to hatch in 24 – 48 hours. 3) Normal development of air pocket according to number of days. Procedure 1. Hold egg between the thumb and tips of the first two fingers. 2. Light up the candler and keep egg in the front of light. The room should be darkened 3. The egg must be held in a slanting position with the large end against the hole in the candler. 4. The light penetrates the egg and makes it possible to observe the inside of the egg. The embryo is located at the large end of the egg. 5. The egg is turned quickly to the right or left. This moves the contents of the egg and throws the yolk nearer the shell. Mark with any marker for air cell or any other spot. 6. Any eggs you are not sure of, pencil a question mark onto. Have another look at them later. Dark or brown shelled eggs are more difficult to candle than white or pale shelled eggs. Symptoms Possible cause Eggs candling clear No blood rings or embryo growth. 1. Eggs from a flock having no roosters. 2. Poor flock management. 3. Eggs stored below 40° F or which were too old before setting. Eggs candling clear But showing blood or very small embryos on breaking. 1. Incubator temperature too high. 2. Eggs stored below 40 or above 80° F. before setting. Dead Embryos Before hatching time. 1. Eggs haven't been turned at least 3 times a day. 2. Lack of ventilation. 3. Incubator temperature set too high or too low. 4. Breeder flock having poor hatchability or fed inadequate ration. Eggs pipped but not hatched (Chick pecks hole through shell) Chicks dead in shells. Sticky chicks Shells sticking to chicks. 1. Low average humidity. 2. Low average temperature. 3. Low humidity at hatching time. 4. Excessive high temperature for short period. Hatching too early With bloody navels. 1. Temperature too high. Delayed hatch Eggs not pipping until 21st day or later. 1. Temperature too low. Draggy hatch Some chicks hatch early, but hatch is slow in finishing. 1. Temperature too high.