Hop, bounce, whatever you want to call it, Coons around here end up any place they want to. They will apply siege tactics for several nights until they finely reach their goal. If easier food is available they will not expend the energy to break into something like you are wanting to build. However, if they develop a taste for chicken, get ready for a game of wits. I had a momma Coon pry open a corner seam of a metal building to make a den. My electric fence is just the first line of defense.
Raccoons can't jump - Page 3
Great to have someone with a lot of coon experience.
I promise that coons can jump. I coon hunt with my mtn curs and have seen numerous coons jump on a tree way before being at the base of the trunk.
Long jump is different than high jump. With long jump you have momentum. If they have footing that is at an angle they will have upward momentum.
You may stand less of a chance of a coon getting in based on the site you provided. But I assure you they can and will jump if they are hungry.
The claim was on the site in February 2005, and it was updated in April 2008 . It is not a commercial site so they probably would've admitted it if they had evidence their raccoon proofing had failed in that time. Perhaps the coons didn't leave any evidence. Coons would probably be a lot more motivated to get poultry rather than cat food. (I emailed them on the 30th of April, 2010, to ask about these things. It is now May 18th and I have not received a reply.)
The site says "The 4x4x8 is pressure treated and set 3' into the ground" so that means the grab point should be 5 feet plus a few inches for the bracket and table width. For the long jump off their "cat launchpad" this site says "[t]his distance is about 2' from the base of the 4x4" which I guess refers to distance to the edge of the little house.
Your guess is probably better than most. What would you say is the absolute highest that a coon could possibly jump and grab with their front claws? Consider this from two scenarios: First is a coon running full speed and leaping from the chicken lauchpad bar. Second is a coon jumping and reaching straight up off the ground.
Next question is, could a coon get higher than a agile/small canine who could get through/under the run fence and past the S-shaped corridor I suggested? [Update: Although they have not explicitly said so, Katy and Pat seem critical of the S-shaped corridor. If (large) high-jumping canines could get past the S-shaped corridor, the coop "should" only be open to a run made with welded wire and a dig-prevention apron, or the climb-prevention barrier must be higher than any canine can jump. We have to plan for the height that a canine can jump, rather than a raccoon, or the coop can only be open to a run that is canine-proof. If a canine can get in the coop, it seems to me the poultry would be better off not being in an enclosure. This still may work where canines are not around, for example, in a yard protected by a electric fence and dogs (IF the only significant threat is still opossum).
[Updated to delete some of my older speculation and add my "more educated" speculation, which is in bold.]
Edited by Lumenos - 5/18/10 at 7:12pm