That flat piece of plate, in the middle of the back edge of the deck and extending up to the wheel support assembly, measuring about 2" x 9" or so usually has multiple holes in it. If not, I'd drill several about 1-1/2" apart. Moving the tricycle up or down and bolting through a different hole should be all you need. HOWEVER, with the whole thing bent and the wheel laying somewhat on it's side, it's never going to work well. Get it straightned before something breaks again.
I just noticed, that maybe the arms are welded rather than bolted at the front of the wheel assembly. If that's the case, I'd change that too, otherwise, nothing's moving.
Out at the front end, I'd suggest "check chains".
There should be a hole and then a washer (or even a couple) and then a cotter pin to hold the wheel spindle in place when the hog is lifted.