A rotary drum mower is a tractor-mounted harvester used for harvesting green fodder plants in agricultural fields. During transportation, it experiences significant dynamic road reaction forces that can cause deformation and functional failures. This study focuses on analysing the deformation behaviour of the machine during transportation to test the machine’s failure condition. To conduct the strength analysis, a total work cycle scenario reflecting actual load conditions and design challenges was created. Experimental strain-gauge-based stress analysis and advanced computer-aided engineering (CAE) simulation methods were employed. The study successfully conducted experimental stress analysis, 3D solid modelling, and validated finite element analysis (FEA). A comparison between experimental and simulation results showed an average relative difference of 24.25% with a maximum absolute difference of approximately 5 MPa. No functional failure issues were observed during physical experiments. The study also revealed that the mean dynamic loading value, when compared to the static linkage position, was calculated as 3.65 ± 0.40. Overall, this research provides a valuable approach for future studies on complex stress and deformation evaluations of agricultural machinery and equipment.