Need ideas for hay feeding tubs

I’m struggling with how to feed hay to my mare in her current situation, and welcome any and all ideas!

A few months ago my horse’s paddock was redone to be mud-free, which is awesome, but the top layer is now like an arena sand, that makes me worry about sand colic. She eats off the ground, and is out 24/7 except for bad weather.

If she were a normal horse, I’d put her hay in a big tub or a net and call it a day. However she has respiratory issues and therefore can’t have her hay in anything where she has to stick her nose in a small enclosed area.

I’ve tried just a mat but she pushes the hay off of it, thus defeating the purpose. After talking to my vet, she suggested a shallow, wide tub with shorter sides that she can still spread the hay out in. She only gets a max of 2 flakes at a time (4 feedings per day). One last complication is that her paddock is on the smaller side so I’d like to keep whatever I get as small as possible.

Would something like this work? Any other ideas COTHers have tried?

https://www.tractorsupply.com/tsc/product/tuff-stuff-products-heavy-duty-oval-stock-tank-15-gal

I would just put out several mats , making a larger area and hope for the best. Anything I put my horses hay into only works when they are not eating. The first thing they do is fling it out to see what is on the bottom. Every. Single. Time. Without fail.

Mine eat off dirt/ sandy soil and have never had an issue.i do put it on several mats and it helps.

Maybe put your money toward feeding that supplement for sand ingestion if you are worried.