Were I you, I'd get my act together and beg someone to get rid of your posting. Ripping apart the way the man paying you chooses to run his business on a public forum? Pretty dumb, if you ask me. This might not be Facebook, but its a pretty popular site.
I'm not truly against people having a better idea of how to do something.. That's how better products and business come about, but I'd keep those feelings to myself until I could afford to find myself without a job, or better yet, had the collateral to start my own business.
As to the matter of the "useless crippled mare," who are you to determine that? I've been told many times that its "time to ship my old Paint gelding out," as he's just a big pasture ornament now.. But I would never consider getting rid of him.. Were I in a position to only feed one horse instead of four, he'd be the one I wouldn't try and find a new home for. If he's taking care of this mare, be that by doing so himself or paying someone else (you, of all people) to, then you should just zip those lips and get to work.