They're very restful creatures. All girls (I think). Julia says she's seen them cantering, but I've only seen them standing still. "Megalith still" as Ted Hughes has it.
Think of them as self-propelled lawn-mowers.
Juia says this one isn't in such good condition. Her shoulder muscles and thigh muscles (I expect there are technical terms for them) are wasted. That probably means she's been kept tethered or in a stable with no opportunity to run about.