I give and have given my buns local hay for a very long time. I only give pet store hay when I cant get local farm hay. It’s horse hay, a mix of grasses, mainly timothy but not all timothy.  The only observandum with horse hay is that it sometimes contains quite a bit of alfalfa. Alfalfa is good for horses but too rich in protein and calcium for adult rabbits.

A rabbit that gets a lot of human attention can live happily as an only-rabbit. Rabbits as a rule benefit from a same-species friend, but not all rabbits will accept another rabbit.

It’s good that you’re keeping an eye on your buns weight! Weight is a very important indicator of a buns health, since they’re very good at hiding any type of illness or discomfort. Unexplained weightloss in a young-ish bun can be caused by many different things, ranging from easily fixed ones (tiny molar sprs f ex) to more serious ones (f ex kidney or urinary tract problems).

I also have given my rabbits only local hay for a very long time. They love it! And grass hay that’s meant for horses is acceptable. Usually timothy is the only thing available in my area. I do check it for weeds as I feed them and remove any I don’t recognize as safe.

It’s good you are paying attention to weight loss. If hay consumption has gone down, it could be he doesn’t like this bale (sometimes there is a weird batch), or it could be something else (like a dental problem).