Next generation use-cases of wireless mesh networks, especially the Massive Machine Type Communications and IoT applications require the capability to handle a large number of connections while maintaining a low-energy usage. In such cases, the transmissions between source and destination can employ multiple paths. The throughput in a scenario like this can be maximised with application of Opportunistic Routing (OpR). In high density networks, the OpR uses the diversity of the broadcast channel to increase the achievable data rates in comparison to traditional routing solutions. However, the header size of the routing messages increases when the density grows. The reduction of this overhead could potentially improve the overall throughput and decrease the battery usage of network heavy applications via diminished wireless interface activity. Normally, header compression is employed to minimise the overhead of IP-based cellular traffic between two connected peers. This paper presents for the first time the application of header compression concepts to an opportunistic routing protocol. We use a packet erasure channel simulator to employ these header compression techniques on the routing messages based on real world mesh network traces. We thereby decrease the size of the routing messages in these simulated topologies and find that they can reduce the size of transmission heavy header elements by at least 50 % and can be even as high as 85 % under certain conditions. This increases the potential of opportunistic routing in very large mesh networks, as the reduction in feedback message sizes would increase the maximum achievable data rates exponentially.