Chaff making pony cough?

[Christmas Crumpet]

Our pony has started coughing but it only seems to be after feed time and a couple of times riding. She has fast fibre and top chop zero. Does chaff make them cough? Never had it before and it’s always properly wetter down.

otherwise what can I put in with the fast fibre so it’s not just mush?

 

[Pearlsacarolsinger]

Horses can react badly to just about any feed, even grass. One of the symptoms of a reaction can be a cough. I had a mare who had been seen by the vet several times over the years and prescribed Ventipulmin frequently. The cough actually resolved when se stopped feeding her cereals and sugar.
You could add grass chaff, or a plain oat straw chaff, such as Honeychop to your FastFibre.