Bone formation and resorption are stimulated by mechanical loading. Musculoskeletal disease or injury that immobilizes forelimbs can cause altered bone formation that has lasting effects on bone structure. This study aimed to isolate the effects of mechanical unloading in the development of the glenohumeral joint, with an eye toward injuries that affect glenohumeral development such as brachial plexus birth injury (BPBI). Two unloading forelimb models and a control were developed to analyze the micro and macrostructure of the scapula and humerus in neonatal rats. The first model unloaded the glenohumeral joint through amputation at the elbow;​ this model resulted in reduced bone volume, glenoid deformities, and degradations in trabecular structure in the scapula and reduced trabeculae in both the scapula and epiphysis of the humerus compared the control group. The second model unloaded forelimbs through suspension;​ this group exhibited more trabecular bone compared to the amputation group and limited differences compared to the control. Suspended forelimbs, while unloaded, had mobility to carry out forelimb activity such as grooming and feeding function, similar to that seen in control animals, and resulted in bone growth more similar to the control group. This suggests that normal glenohumeral development may be stimulated by small loads, which has significant implications for prevention and treatment of the injured or immobilized developing forelimb. While this study was initially developed to better understand how loading affects the mechanical properties of the developing shoulder as seen in BPBI, these observations are a foundation to develop methods to prevent and treat bone deformities arising more broadly from disuse and perinatal nerve injuries.