I have a hard to catch horse. Or rather, I did. I’ve owned her for something like 6 years and she was always a pain to catch. She wasn’t overly food motivated, so going in with a bucket of something yummy didn’t really phase her. She didn’t like the look of a halter/lead rope in my possession. Sometimes, it would take me 4 or 5 hours of walking her down before she finally gave up and let me catch her. Fortunately, I am strangely patient and tenacious. The only time she was somewhat easy to catch is if she was in a smaller pen, but then she was dreadfully unhappy… losing weight, getting sore and lethargic and it just wasn’t good. She thrives in a larger paddock so I just accepted I’d always have to expect a few hours to catch her.
Last year, I started leaving a halter on her all the time. I use flimsy leather ones and she’s managed to lose 2 or 3 since October. But she was marginally better to catch. Not great, but it no longer took hours to catch her.
Then someone made a very off-hand remark about her routine. She’s a Standardbred and they thrive on routine. On the track, they have schedules every day, right down to the time they are fed and turned out. So I started building her a routine. Whenever I’d enter her paddock, I would hold out my hand flat, call “Vanna…coooooookie” and walk up to her. When she took the cookie from one hand, I reached up and grabbed her halter with my other hand. I would clip the lead rope on, then I’d spend a couple minutes scratching her itchy spots. Then, we’d leave the pen.
I’d lead her up to my grooming area, tie her and give her lunch. She would eat that while I groomed her. Then, she’d get more scratches, I’d tack her up and we’d go on whatever adventure I had planned. When we came back, she’d get untacked, I’d give her a cookie and I’d brush her and get her ready to go back to the field.
Once in the field, she would get more scratches and I’d give her a cookie before turning her loose.
After about a week, she started realizing that the same thing would happen every time I took her out. She started popping her head up and meeting me halfway when she heard me call her name. After another week, I could wait at the gate and she would come running to me. Now, I can call her name when I’m walking up to the field and by the time I get there, she’s waiting for me. When I turn her back out, she doesn’t just run away… most times she’ll follow me around after I’ve turned her loose, in hopes of an extra neck scratch or something.
Giving her a routine and sticking to it made all the difference in the world. Prior, I was doing all these same things… but randomly. Once I started sticking to a routine, it was like she knew exactly what to expect and she was 100% more comfortable with leaving her group. She knew there would be a cookie waiting, she knew she’d get scratches, she knew lunch was soon, and she knew that I’d always bring her back afterward. Maybe that’s something your horse needs, OP, a set routine of things you do every single time you see her, in the exact same order. It’s probably worth a try. 
