T1-11 is in the plywood section and it is heavy. You will find 2 different thicknesses of T1-11 one is essentially a 1/2" and the other is 3/4". T1-11 is very expensive since it is a real plywood siding. There are 2 alternatives that look like T1-11. One is a MDF siding which will work but will need to be caulked and regularly painted. The other is an OSB material which will be somewhat more durable than the MDF style wood. Neither of which come close to the durability of true T1-11 and thus explains the cost difference.@Flowerbh, I am so very thankful for the wonderful advice. You are right, cedar is a no-no for chickens. One of the books I have said shavings were the problem but boards were ok, doing some research I found evidence to the contrary.
I see T1-11 mentioned a lot, I have not seeing it a HD/Lowes, but will look for it more carefully. I hope it is not too heavy. That is the hardest part about trying to make this a moveable tractor, finding lightweight materials that are suitable.
I looked for others that had used the corrugated plastic and found mixed reviews. It seems that the polycarbonate is ok, but the cheaper one is not as good. I also see that it can be hard in the heat, planning on having them moving around in the woods/ shaded areas for summer, so hopefully that will work. I am thinking they will only "work" the veggie garden where is very sunny in the late fall to early spring.
thank you again!