Simple Summary: The genetic basis underlying the development of different adipose tissues in broiler chicks requires extensive study. The molecular mechanisms and specific transcripts associated with fat development and deposition remain unknown. However, little is known about the relationship between the changes in the expression of genes and fat development and deposition in chickens. Thus, the molecular mechanisms regulating the development of different adipose tissues may differ. Hence, studying the mechanisms regulating the growth and development of different adipose tissues during the early stages of broiler development is important in poultry breeding. Therefore, in this study, RNA-seq analysis was utilized to reveal the molecular mechanisms regulating the development and deposition of different adipose tissues in broiler chicks. The results obtained showed that genes such as MYOG, S100A9, CIDEC, THRSP, CXCL13, and NMU were related to the growth and development of adipose tissue. Further, genes such as HOXC9, AGT, TMEM182, ANGPTL3, CRP, and DSG2 were identified to be associated with the distribution of adipose tissue, and MN1, ANK2, and CAP2 were related to the growth of adipocytes. Therefore, the candidate genes identified in this study could be used in chicken selection to increase or decrease specific adipose tissues in broiler chickens. In an effort to enhance growth rates, chicken breeders have undertaken intensive genetic selection. In the selection process, the primary aim is to accelerate growth, inadvertently leading to new chicken breeds having an increased capacity for rapid adipose tissue accumulation. However, little is known about the relationship between changes in gene expression and adipose tissue accumulation and deposition in chickens. Therefore, in this study, RNA-seq analysis was utilized, and transcriptome data were obtained from the abdominal fat, thoracic subcutaneous fat, and clavicular fat on day 1 (d1), day 4, day 7, day 11, and day 15 to reveal the molecular mechanisms regulating the development and deposition of different adipose tissues in broiler chicks. The results showed that the key period for adipocyte differentiation and proliferation was between d4 and d7 (abdominal fat development) and between d1 and d4 (chest subcutaneous fat and clavicular fat). In addition, candidate genes such as MYOG, S100A9, CIDEC, THRSP, CXCL13, and NMU related to adipose tissue growth and development were identified. Further, genes (HOXC9, AGT, TMEM182, ANGPTL3, CRP, and DSG2) associated with the distribution of adipose tissue were identified, and genes (MN1, ANK2, and CAP2) related to adipose tissue growth were also identified. Taken together, the results from this study provide the basis for future studies on the mechanisms regulating adipose tissue development in chickens. Further, the candidate genes identified could be used in the selection process. [ABSTRACT FROM AUTHOR]