Pet foods are notorious for having frequent recalls -- at least cat and dog foods. I've never heard of a recall on rabbit food, however. Sherwood food is one in which I have full confidence. I've used theirs for years. They make their pellets fresh.
There have definitely been recalls on rabbit pellets, though the ones that I'm aware of have primarily been bulk feeds from farm stores, One major one was several years ago here in Utah. There were a couple feeds where their vitamin mix ratio used in their pellets, was changed by the supplier and not properly labeled. The change ended up causing the final pellet to contain toxic levels of vitamin D. The result was several hundred rabbit deaths due to the effects of vitamin D toxicity. All these rabbits were getting sick and dying, it was tracked to the feed, and it did get pulled.
An alfalfa based pellet isn't necessarily bad if it isn't fed in excess where it causes excess calcium excretion in the urine, which also ends up overworking the kidneys,, or causing a build up of calcium sediment in the bladder. And also when it's not fed in excess where too much protein in the diet is causing excess cecals or a strong ammonia smell in the urine. Though if feeding alfalfa pellets that are high in protein, to an adult rabbit, you would likely need to feed much less than if feeding a lower protein grass based pellet.
Diet is all about finding the right balance for your rabbit, where what is being fed isn't leading to health problems, but is keeping your rabbit healthy and at a healthy weight. You'll get hundreds(or more) opinions on what the best diet is. It's good to take into account other's opinions, but I would be more inclined to listen to those opinions if they are based on those persons own experiences and not just being relayed based on something they read(unless factually based on research). Sometimes it's a matter of learning by experience. But also know that sometimes that experience is gained by something negative occurring. I've had rabbits with bladder sludge issues. I ended up feeding grass based pellets because of the experience I gained by trying different pellets, including a few alfalfa based ones like sherwood.
When trying to sort out what the best diet is, I would recommend keeping a close eye on poop and urine output, as well as your rabbits body condition, and monitoring for abnormal changes of behavior. Looking at what the poop size, color, and consistency is. Looking at a urine spot absorbed onto newspaper to see if it contains a lot of calcium sediment, if it's thick and creamy or gel like, if it contains grit, if there are any blood spots. Making sure your rabbit is maintaining a healthy weight on the diet you are feeding. Then always looking for changes of behavior. Regularly checking these things is how best to catch a problem developing before it becomes a serious health problem. Then if there is a diet related component, you know that something needs adjusting or changing.
