What I do is read the macro nutritional-values list on the package. I also read the ingredients-list, but the that only says so much, because feed companies mix the ingredients to fit the desired nutritional values. You dont get any info on the micro-nutrients though, because that’s not legally required.

The pellets I am using for my adult mini rex (a breed that’s prone to putting on weight) have these specifics:

It’s not a brand you get in the USA, but you can most likely find sth with similar nutritional contents. 20% crude fiber is considered a (good) minimum though, if you can get higher than that, it’s great.

The bulk of an adult rabbit’s diet should always be hay, as I’m sure you know. Hay is a lot more important than pellets or greens. It’s good to serve a variety of hays,  because hays are not uniform. Hays vary not only by grass type, the nutritional contents also depend on when in the season the hay was cut, how much sun it got, the soil it grew in, the drying process and storage.

Pretty much any hay that horses eat, (except alfalfa, alfalfa is great for baby buns but too rich in protein and calcium for healthy adult buns) is good for buns.

It could be more an issue with amount over pellet type. If you check out this pellet comparison chart it can help you compare brands: https://wabbitwiki.com/wiki/Rabbit_pellets_comparison_charts

How much pellets are you feeding each day? At age 5 they really don’t need very many pellets at all. At one point I had an adult/senior bun that was overweight and the vet had me cut out pellets entirely.

1/8 cup 2 tbl spoons) is a suitable amount for a 2 kilo (4 lb) bun, but if your bun is a little bit chubby you could lower it to 1 or 1.5 tablespoons and give half the daily amount in the morning and half in the evening.

Many good brands.  Just avoid ones with fillers (corn, wheat, soy, etc.). And the types with all the “goodies”.

Also, it’s surprising how many pet foods contain sugar…why?  Obviously those aren’t good at all.

I wanted to add a few good brands to help you look.
– Sherwood ( what I feed my bunnies )

– oxbow

– small pet select

These are just a few and there are many more. Maybe talk to your vet about what they think would be best. Also what hay are you you feeding him/her alfalfa and oat? Those are linked to weight gain in adult rabbits.