The gene sequences of Growth hormone (GH), Insulin-like Growth Factor 1 (IGF-1) and Myostatin (MSTN) were downloaded from National Center for Biotechnology Information (NCBI) database, through Entrez of the database as non-redundant reference sequence in FASTA format, using respective accession numbers of the various genes in the GenBank to access the necessary gene information. They were subjected to different computational tools, on-line softwares and programs; for Multiple sequence alignment, phylogenetic tree, BLAST-like alignment tool (BLAT), Basic Like Alignment Search Tool (BLAST)were used to analyzed for gene number in a genome, exon type and number per gene, number of codons per gene; gaps within the alignment of the three species for each gene; single nucleotide polymorphism between the alignments of chicken by rabbit, chicken by sheep, and rabbit by sheep; the conserved regions between the alignments of chicken by rabbit, chicken by sheep, rabbit by sheep, and chicken by rabbit by sheep and other parameters by submitting the genes respective sequences in FASTA format to the tool. Results indicated that higher body weight and size of sheep might have been due to two categories of GH, high gene number of GH, high exon number of GH, long sequence length of GH which resulted to higher predicted coding sequence and higher predicted peptide size. Rabbit and chicken never shared common ancestor in GH, the number of chromosomes GHgene distributed in sheep genome was higher than that in rabbit and chicken, and all are found on the opposite strand (negative). Rabbit and sheep once shared common ancestor in IGF-1 and MSTN gene. Rabbit and sheep IGF-1 has longer gene length, higher number, exon number, predicted coding sequence, predicted peptide size which might have been the reason for higher body weight at maturity compare to chicken. It is concluded that; the number of GH gene of sheep is higher than that of GH of chicken, than GH of rabbit but the number IGF-1 gene of rabbit and sheep are higher than that of chicken IGF-1 gene, while the number of rabbit myostatin is higher than that of chicken and sheep Myostatin. The number of genes in chicken, rabbit and sheep genomes plays a key role in establishing effective gene function. The genes shares some conserved regions but the length/size, gene number, exon number, exon type, number of gene/genome, gene DNA strand, codons/gene, gaps, SNP varied greatly among chicken, rabbit and sheep species. The gene conserved regions similarities are for conserved functions while, the differences are for different expression pathways among the three species. Myostatin gene depresses animal growth process through the action of IGF-1 gene. Frame shift mutations in the upstream or downstream regions of the genes, lead to differential gene regulation without actually changing the structure and functions of the protein. It is recommended that; Chicken and sheep growth could be improved through increasing the length/size and number of their IGF-1 gene by gene modification techniques. Rabbit growth could be improved through increasing the length/size and number of the GH gene by gene modification techniques. Some missing nucleotides in rabbit and chicken GH and IGF-1 gene sequences could be modified by gene modification technology and use as a useful marker for economic traits. It is recommended that more experiments could be conducted to knock-off or knock-out some of these extra length sequence regions of sheep GH and IGF-1 gene not found in rabbit and chicken GH and IGF-1 gene, when aligned.