An easy way to do an A-Frame run attachment, to give them more room.
Using CP (cattle panel) as your A-frame. You could do it with a wood base, a aluminum or conduit (think the poles on a chainlink fence) or pvc. I did do one for a time w/o the base at all - but in my case it made the actual tractor very difficult to move. If used just as a run extension, it could certainly work with out a base at all.
Over the CP, you can put 2x4" wire or hardware cloth like on your original. You can use a wood frame similar to what you already have. I did read about another one today that is hinged at the top and has a rope attachment to hold it at a certain distance. That one is not meant to be used if a person is not handy.
Ours are simple, have used some new and some re-cycled materials. Other than the base and the roost, there is no wood on mine. Easier for me to build (I have a hard time w/ those "fancy" angled (mitered) measurements and then fitting,

Our wheels are not yet on ours (we have 4 - they are 5x8'), nor do i have my feeders or a good waterer in them. I may try out your water idea, not sure... Was going to do the two buckets for feed/water. Nifty ideas!
OR you could make a run attachment that totally matches your current tractor.
Hmm, my pics seemed to have disappeared. I will need to find them!