In a previous life went through several trials with this issue, used to deliver either palletised goods or wheeled cages, or a combination of both. In a nutshell drew up a method of how to unload 2 cages at a time - moveable wheels against tail lift flaps on the LHS of the tail lift and the driver stands on the RHS and operates the buttons to lower tail lift. With pallets they had to be pushed onto the tail lift (big no no walking backwards onto tail lift platform). Put some markers in the back of the trailers to indicate to loads where they could load pallets up to - which then gave a driver some room to manouvre the pallet before putting it on the tail lift platform. Looked at weights of cages and pallets also, and gave drivers an instruction that if they thought it was heavy they could break it down prior to movement. None of the above very scientific, but did reduce accidents significantly. Final point, reviewed all available CCTV for every accident at a delivery point - majority of accidents occured when the above guidance wasn't followed. Gave my union rep responsibility to give briefings out to all of the drivers - lots of benefits from this aspect as he came up with some really good ideas. Did try small straps to hook onto the bottom of the cage and the tail lift platform.....these were okay but the 30 I had on trial were lost very quickly. Good luck.