Birds, time and place of the experiment: The experiment was conducted at Bangladesh Agricultural University (BAU) Poultry Farm, Mymensingh during November 2008 to May 2010 using the Wild type and 5 newly-isolated color mutants of Japanese quail. The newly-isolated color mutants were (proposed name) (a) BB-white, (b) BB-Black, (c) BB-Dhakaya, (d) BB-Rosseta and (e) BB-Tuxedo. (BB-white; White colors on whole body except a black or brown spot on top/back of the head or sometimes at back / tail. BB-Black; The whole birds looked very dark and the black and brown feathers were mixed. The shank color is gery. BB-Dhakaya; Bird with black and tan marking over a cream base. BB-Rosseta; Cinnamon colored with white lacing. BB-Tuxedo; Dark brown on the dorsal surface and white on the ventral surface. The area of white ranges from the total ventral surface to just a white band across the breast and a patch of white under the throat). Comparison of egg prodiouctn and egg quality: To compare the rate of egg production, 48 female and 16 male of 8 week old from each color variety were housed in 3-tier cages keeping 6 female with 2 male in each of 35.56cm × 35.56cm× 30.48cm = 38542.38 cm3/pen. The birds of each color e were supplied with 25g/ day commercial layer mash supplemented 3% protein concentrated plus free access to safe water. The egg qualities, like egg weight, yolk weight, shell membrane weight, shell thickness, egg shape index, albumen index, yolk index, yolk color score etc measurements were performed on 60 eggs taking 10 eggs from each the color mutants. The weight of the egg was recorded by electric balance. The egg shape index was calculated from the width and length of the egg. The albumen index was determined. The yolk index was the ration of the height and width of the yolk measured by micrometer and slide calipers, respectively. The eggshell thickness and shell membrane were measured. Yolk weight was taken after separating the yolk from albumen with the help of blotting paper and forceps in a decantation method. The yolk weight was expressed as the % of egg weight. The yolk color score was determined by comparing the yolk color with that of standard values of Roche Yolk Color Fan (F, Hoffrnan-La Roche Ltd.). The values were expressed on a 1 to 8 point color scale that indicated very light yellow to deep yellow color. Comparison of hatching performance: Three separate batches of hatching eggs were set for testing the hatching performance. In each batch, at least 100 eggs from each color mutant were collected and d for maximum 7 days and set within the sanitized incubator. The measured parameters under hatching performances were the rate of fertility, hatchability, embryonic death and day-old chick weight. The eggs were incubated for a total period of 17days, where the first 15 days were setting period and the last 2 days were considered as the hatching periods. At the end of setting period, the eggs were transferred to a designed hatching tray where the chick from an individual egg could be easily recognized. A constant 38.5 and 37 ? temperature and 65 and 85% relative humidity were maintained during setting and hatching periods, respectively. The automatic turner was switched turn the setting at 1 hour interval. The weight of the hatched out chicks was recorded by an electric balance. At the end of hatching period, all the un-hatched eggs were opened to examine the exact period of embryonic death within the incubator comparing with the normal embryonic development of quail. The embryonic death was recorded by dividing the whole incubation periods into 3 slots; d 0-6 and d 7-12 of incubation and d 13-to hatch out of chick. The percentage of fertility and hatchability was calculated on the basis of total eggs set using the formula. The chicks weight was expressed as the % of egg weight. The total embryonic death was expressed as the % of fertile egg set whereas; the incubation period wise death was the % of total death within a mutation during the whole incubation period. Study on growing performance: After hatching out of the chicks, their growth rate, body weight, survivability and disease occurrence were monitored in 3 batches giving at least 50 males and 50 females in each of color mutant of quail up to 42 days of age. The growing quail chicks were reared on littered floor supplying same amount of commercial broiler starter diet. The 23, 59, 87, 104, 129 and 133g feed/ bird/ week during 1st, 2nd, 3rd, 4th, 5th and 6th week, respectively was supplied daily to all mutants. The weekly body weight gain in different color varieties were recorded from randomly selected 5 males and 5 females. Determination of the carcass characteristics: At 42 days of age each of randomly chosen 3 male and female quail from 6 color mutants was slaughtered and dissected. The live weight, bloodless and featherless weight, and head, shank, feet, gizzard, heart, liver, proventriculus, skin, skin fat, breast, thigh, drumstick, wing, back, neck and alimentary tracts weight and the length of alimentary tract were measured and recorded. All data were converted into percentages of live weight with its live weight and multiplied by 100. Statistical analyses: All data on laying, growing and hatching performance, mortality rates and carcass characteristics were analyzed by the Genstat (Fifth edition, Lawes Agricultural Trust, Rothamsted Experimental Station, Germany) statistical package. The data were arranged for a Completely Randomized Design (Steel and Torrie, 1980) for Analysis of Variance (ANOVA). Least significant differences (LSD) for a parameter were calculated and used to find out the significant difference among the color mutants.