Is he sneezing or trying to crow? He looks healthy but it is possible he has an allergy to dust, so make sure the environment is kept as clean as possible.
@shahab if it’s an allergy causing it then ribwort plantain might help, it’s a pretty strong antihistamine.
You could feed the leaves and seeds to him or make a tea with the leaves and put it in his water. It’s totally harmless stuff, you can eat it as a salad crop, tastes a bit like broad beans.
It’s like people say about rats in London, you’re never more than a metre away from one, they’re everywhere. The fat leaved one with more seeds or the thin leaved one with a smaller seed head work just as well as each other, there’s a cultivated one with stag horn type leaves you can get seeds for, doesn’t really matter which.