“…Sobczak and Kozłowski (2015) indicated that the addition of Bacillus subtilis as a probiotic at a level of 1.4 × 10 8 (cfu/g) per kilogram of ration, did not affect the product characteristics, which included: egg weight, number of eggs, egg mass, feed consumption and feed conversion, and it was observed there were significant differences in the weight gain of laying hens, and it also did not affect the qualitative characteristics of eggs, which included: white weight, yolk weight, but a significant improvement was observed in shell weight, thickness and average yolk colour when studying 288 laying hens of the Lohmann Brown strain. For 26 weeks.In a study conducted on 112 laying hens at the age of 42 weeks, the Sheffer breed, which aimed to know the effect of adding the locally prepared probiotic on productive performance, as one gram of the probiotic contains no less than 10 10 (cfu / g) of Lactobacilli bacteria And no less than 10 10 (cfu/g) of Saccharomyces cerevisiae, no less than 1 10 (cfu/g) of Lactobacillus acidophilus, and no less than,100 10 (cfu/g) of Bacillus subtilus, the probiotic was used in this study in different proportions. (5, 10 and 15) Alagawany et al (2016) found that the addition of probiotics had no significant effect on the amount of feed consumed, feed conversion factor, egg weight, egg production percentage (HD%) and egg mass in a study conducted on 160 laying hens the Lohmann breed, for 20 weeks, in which the probiotic was used at the level of 1 g / kg feed, which contains Lactobacillus acidophilus in an amount of 10 10 (cfu/g).…”