I'm having a lot of trouble with my 17yo TB mare in the horsebox. She has had an accident in a lorry about 5 years ago but I'm not sure of the exact details, she just has a huge scar on her left hip. She will not travel in a lorry but recently she has also started to play up in the horsebox. When going around a corner she leans to the right and kicks violently. We have had various incidents with her when she will not stop kicking or get out the box even when it has stopped. Her most recent panic attack was the scariest: around a corner she started kicking and leaning, then fell. She kicked and struggled to get up and was terrified. We took my other horse out but she couldn't get up for some time, and we just let her lie still for a while. We eventually got her up and tried to close the partition again, but she tried to lean over again, so we had to take her out and send her home on foot.
We normally manage to get her to local shows without mishap, but we can't take her to away shows, and I'd love to because she's my best horse, jumping 1,20m at the moment.
Some people have suggested giving her equimote (an antidepressant) to calm her down, or putting her in a sling to stop her falling or even sedating her before traveling!
Does anyone have any ideas that could either help to keep her upright when she leans or to stop her kicking? And would any of the above suggestions work? Many thanks