Looks like your front straps are not doing anything to hold the machine down but rather keeping it from rolling backwards. Even pulling it forward if something happened to chains in the rear. I have chains and straps but feel totally confident that my straps will hold mine DOWN.
Did you add those hooks on the rear, like those. Welded or bolted on? More pics of them, please.
Looked again at rear hooks and noticed you also have back being pulled back with chains instead of DOWN. If front straps were to break then you'd have a loose tractor with lots of rolling potential also assuming the brakes that should be locked on are not able to hold the tires on that wood deck. My:2cents: is you need to strap it DOWN instead of being pulled front to back or back to front.