Wow, looking great Josepha! I hear you on the mud...
This has been our battle too.. determined to keep horses out of stable.. but having so many in a small space it's sooooo hard to deal with the MUUUUDDD! Looks like you have found a workable solution.
I used to worry about how FLAT our paddock was.. and how small.. especially with a few horses who had metabolic issues and needed movement and a few older who need topline rebuilding and strengthening. One idea I came up with .. and I"m just mentioning it because I wondered if it might be useful to you in your situation.. was to put some "logs" on the "trails" that they have to use. This provided passive conditioning.. like a single cavaletti but in the right place it could be used many times in one day and thus provide valuable tummy and back trimming. I also put obstacles in their "living room" so that they couldn't walk straight lines everywhere and had to turn and bend a little.
And for interest and a bit of Dr Green we made a double fence with chain link mesh each side a metre apart and planted things that they would like to eat inside... they can only reach the tips that sprout through. One day I woke up and told my husband we needed hills.. and next week little hills appeared.
They're all little things.. certainly don't make it the high country station that I'd like to give them.. but I think it all helps.
I love your hay feeders! Did you design them yourselves?
It's so much fun redecorating isn't it!
I have not sought the horse of bits, bridles, saddles and shackles,
But the horse of the wind, the horse of freedom, the horse of the dream. [Robert Vavra]