The common housefly (Musca domestica) is found in all parts of the world. Its ability to live in various habitats makes some of its life cycle stages, such as larvae and pupae, to be freely available as food for foraging poultry kept on free-range systems. There are two key challenges facing large commercial poultry farms worldwide. One is the low supply of animal proteins and the other is the excess organic wastes generated from poultry farms. Common housefly prepupae proved to be the solution to these two main challenges: its ability to valorize the organic wastes and its excellent nutritive value. The study was conducted at Farhan Farm in Msabaha, Kilifi County, Kenya. The objectives were to evaluate the growth performance of M. domestica prepupae reared on selected broiler by-products and determine the nutritive value of M. domestica prepupae reared on selected broiler by-products. A Completely Randomized Design (CRD) replicated three times was used. The selected broiler by products in the study which served as treatments were broiler manure, blood, crop content, intestinal rejects, and broiler. Laboratory analysis for the nutritive value of the prepupae was done at Kenya Agricultural and Livestock Research Organization (KALRO) Kakamega. R-Statistical software was used to analyze the data, a One Way Analysis of Variance (ANOVA) was done followed by a post hoc test of Least Significance Difference (LSD). There was a significant difference in the growth performance of common housefly prepupae based on; eggs hatchability, time taken from 1st instar to 3rd instar of the prepupae, mean mortality, and an average weight of prepupae concerning treatments applied. Findings from the laboratory showed that M. domestica reared on dead broiler had the highest crude protein (45.83%), compared to those reared on blood (41.54%), crop content (33.18%), intestinal rejects (33.14%) and, manure (30.65%). The difference in growth performance and nutritive value of prepupae from the five treatments showed substrate effect on growth performance and nutritive value of M. domestica prepupae, hence the need to select the most performing broiler by-product for rearing the prepupae. Broiler blood, intestinal rej,ects, and crop content in that order gave the best result as per the two objectives of the study and can be adopted as safe substrates for rearing prepupae as an nimal feed with a deep focus on improving food security while keeping our environment safe from broiler organic wastes.