Before we can install the front roofing we need to build most of the Aviary. So that is what this step is. Remember that corner you cut off the 2X4s at a 45 that I said to discard, un-discard it. Sorry. Take the two aviary sides you cut back in step two and lay them on the ground with the long sides facing each other. Then add a 1X4 to the bottom of each side using your short sheet rock screws from the OSB into the 1X4. Like this.
Now take your un-discarded 45 and install a piece of it to each aviary side, once again screwing from the OSB into the 45 degree 2X2. be careful to ensure no screw tips protrude from the 45s as this could harm your birds. This goes on the same side as the 1X4s did.
Attaching the aviary sides is easiest with a helper but can be done by one person. Take some 2" sheet rock screws and on 6" spacing start them into the 45 degree 2x2s, so when you attach the aviary side the 2" screws will screw into the square 2X2 inside the loft corner. Take the left aviary side in your left hand and your screw gun in your right hand, hold the aviary side in place making sure the top tip aligns with the roof pitch and screw it in place. Reverse hands and install the right side. It should now look like this.
Measure from the bottom of the Aviary top corner up the side 4 feet and install a 2X4 there. Like this. Then rip a 1X4 and add a 1X2 piece to the bottom half of the 2X4 you just installed. This becomes the stop for the hinged aviary front.
Using 1X4 cut and install a trim piece to each side of the aviary and then down the side of the loft. The vertical side piece needs to run parallel with the edge of the loft end OSB. Like this.
Now lets finish off the roof. Using the four 48" pieces of metal roofing install them on the front of the loft from the aviary 2X4 up.
Now cut and install the two back pieces of metal roofing trim, and then the two front pieces. Then sit back and admire your work.