The minimal amount of cane molasses in Oxbow is really only for flavoring, and Ii'd certainly rather deal with that than the absolutely huge amount of corn in Zupreem. They've also played the splitting game (listing corn and corn gluten meal), I'd be willing to be the real first ingredient is corn, not timothy.
Zupreem's fat content is ok, but they do not list a minimum fiber amount, choosing instead to list the maxiumum fiber amount. That's useless, since you really can't have too much fiber in a pellet, but it's quite easy to have too little. They've also got a pretty high protein content -- house rabbits really only need 12-14%, and theirs is a minimum of 18%. Again, they're playing a tricky game here, because that means it could literally be as high as 100%, but they've covered their butts becuase they've guaranteed the minimum.
The Marshall's that you linked to has a ridiculously low minimum fiber content as well, and the fat is a minimum of 2%, which is high by itself, but it could be higher in that package. The protein in is in a much better than the Zupreem, though.
A good rabbit pellet for an adult rabbit should have a lowish protein (a MAXIMUM of 12-14%) that comes from NON-animal derived sources (some of them do use animal fat), a high fiber content (a MINIMUM of 20%, and higher is better), and low fat (2% max, and I would consider that pretty friggin high). You should avoid carbs like corn and oats (which can upset the GI tract), and alfalfa based pellets (too high in calcium for an adult rabbit) and cheap fillers like beat pulp. Also no seeds or colored bits -- they're fatty and useless and contain dyes typically.
So when you look at the three compared, here's how they break down:
* Crude Protein min 14.00% (no max listed, bad Oxbow)
* Crude Fat min 1.50% (<2%, no max listed)
* Crude Fiber min 25.00% (very ideal, way over 20%, MIN is listed))
* Crude Fiber max 29.00%
* Moisture max 10.00%
* Calcium min 0.35% (under threshold which may contribute to bladder/kidney stones)
* Phosphorus min 0.25% (correctly proportionate to Ca)
* Salt min 0.50%
* Salt max 1.00%
* Vitamin A IU/KG 20,000
* Vitamin D IU/KG 880
* Vitamin E IU/KG 140
* Copper mg/kg 20
Crude Protein 18.0% min (no max listed)
Crude Fat 1.0% min (no max listed)
Crude Fiber 22.0% max (no min listed)
Moisture 12.0% max
No calcium or salt listed, or other vitamin breakdowns. Also only have one forumla for rabbits -- big no-no, growing rabbits have different dietary needs than adult rabbits. They're either really messing somebody up, or kind of half-assing both age requirements.
Crude Protein 14.0% min (no max listed)
Crude Fat 2.0% min (no max listed)
Crude Fiber 16.0% min
Crude Fiber 21.0% max (both listed, but min is too low)
Moisture 12.0% max
Calcium 0.5% min
Calcium 1.0% max (ideally .5% or less of their daily diet)
Phosphorus 0.35% min (disproportionate to calcium. This is a problem because phosphorus is required to adequately process calcium)
Salt 0.25% min
Salt 0.75% max
Vitamin A 2,500 IU/lb min
None are perfect, but Oxbow has the highest fiber which I find most important, and has taken the time to balance out the Ca
ratio correctly and sets their protein fairly low, even though it is a min. I'm also a little biased because I have talked to actual vets on their staff who participate in development of their products, and I know they listen to fancier's and rescue's when they give feedback. (The local Potbellied Pig rescue told me they were working with them to develop a pig food at one point.)