Regarding your siding problem: assuming you've built the structure of the coop on a sensible foundation of some sort rather than just wood lying on the ground, I would agree with some of the above posters that the siding problem looks like splash as much as anything.
As long as the pad is graded properly (does not tip water towards bldg), a splash problem could be mostly-solved relatively easily by 1) install gutters on the building (might have to build prosthetic drip edges, or add flashing, or both), with downpipes leading well away to a lower area; and then also b) put 'something' along the lower edges to protect against any residual splashing. 2' wide plywood leaned against the wall at an angle would probably do a fair bit of good, once you had gutters on (although it'd blow away, I'm not suggesting it as a real solution, just as the sort of situation you're looking for)... you'd have to see what you could think of there.
Regarding moisture in the coop: I'm not surprised, with virtually no ventilation and especially if it has a gravel floor. First you need need NEED quite a lot more ventilation, I'd suggest aiming close to 1 sq ft per chicken (more in a hot climate). Triangular vents up under the overhanging roof peaks would be a start but I honestly think you'll need more. Where you put them is up to you (myself, I'd put some as areas cut out from the wall starting 3' or so above the floor, for summer use, and some additional ones high on the walls - you may have to build little porch roof type overhangs to prevent rain blowing in, since you have no roof overhang to work with).
Second, if your floor is gravel I'd suggest putting something over it. In this situation I might almost argue for rubber horse stall mats (they are not cheap and must be installed carefully over a very flat very well tamped gravel floor, but they will provide a pretty effective barrier to rising moisture). Big square concrete pavers might be an option if stall mats are totally out of the budget. If there is any question at all as to whether the 0floor is high enough to avoid flooding, fix that first.
Good luck,
Pat
As long as the pad is graded properly (does not tip water towards bldg), a splash problem could be mostly-solved relatively easily by 1) install gutters on the building (might have to build prosthetic drip edges, or add flashing, or both), with downpipes leading well away to a lower area; and then also b) put 'something' along the lower edges to protect against any residual splashing. 2' wide plywood leaned against the wall at an angle would probably do a fair bit of good, once you had gutters on (although it'd blow away, I'm not suggesting it as a real solution, just as the sort of situation you're looking for)... you'd have to see what you could think of there.
Regarding moisture in the coop: I'm not surprised, with virtually no ventilation and especially if it has a gravel floor. First you need need NEED quite a lot more ventilation, I'd suggest aiming close to 1 sq ft per chicken (more in a hot climate). Triangular vents up under the overhanging roof peaks would be a start but I honestly think you'll need more. Where you put them is up to you (myself, I'd put some as areas cut out from the wall starting 3' or so above the floor, for summer use, and some additional ones high on the walls - you may have to build little porch roof type overhangs to prevent rain blowing in, since you have no roof overhang to work with).
Second, if your floor is gravel I'd suggest putting something over it. In this situation I might almost argue for rubber horse stall mats (they are not cheap and must be installed carefully over a very flat very well tamped gravel floor, but they will provide a pretty effective barrier to rising moisture). Big square concrete pavers might be an option if stall mats are totally out of the budget. If there is any question at all as to whether the 0floor is high enough to avoid flooding, fix that first.
Good luck,
Pat
