I have same problem with my horses. I swapped them from straw onto wood pellets and the difference has been fantastic! no more coughing and it's so easy to muck out, wish I'd done it sooner. I get it from Liverpool Wood Pellets and the more you buy the cheaper it gets.
Hope you find a suitable...
I thought it was the other way around! that coloureds were becoming TOO popular!
For me, I'm only interested in looking at a horse if it IS coloured! I think they are much more fascinating and unique than any other colour. Once you've seen a bay horse you've seen a thousand IMO :-D...