As you may know, FreeBSD needs Integration Services (drivers and corresponding daemons) in order to work on the Hyper-V and Azure. FreeBSD Integration Service is built in since FreeBSD 10.1. If you want to know feature grids for FreeBSD Integration Service, Microsoft provides full documentation on TechNet.

If you are bringing FreeBSD 10.1 or 10.2 release version from the FreeBSD community or VMDepot to Azure, I recommend you update your FreeBSD 10.1 or 10.2 image with below Errata for FreeBSD Integration Service in Azure to avoid downtime or packet drop. FreeBSD 10.3 has included the following fixes:

• Hyper-V KVP (Key-Value Pair) daemon indefinite sleep: When FreeBSD 10.1 and 10.2 virtual machines run on Hyper-V, the host may not get the expected response of a KVP query. When such a virtual machine runs on Azure, the host may try to recover the “unresponsive” virtual machine by stopping it and starting it later, causing unnecessary downtime. This applies to FreeBSD 10.1 and 10.2. FreeBSD-EN-16:04.hyperv.asc
• hv_netvsc(4) incorrect TCP/IP checksums: If the guest running on Hyper-V is configured as a gateway, the host will silently drop certain packets from the guest.  This applies to FreeBSD 10.2. FreeBSD-EN-16:05.hv_netvsc.asc