Haylage bale sizes?

[domane]

Just want to ask how easy is it to get the "medium" sized bales... the ones that are about 4ft square, as opposed to the small bales or the big round ones. I've always fed dry hay in the past but my new yearling coughs on this unless it's soaked and is fine eating haylage so this year I'm venturing down a new route. I "only" have the two so don't think they'd get through a round bale quick enough and the small bales aren't very economical so I just wondered whether the square sized bales are quite readily available or if they take a bit of searching for....?

Thanks