Two a day of any commercial treat sounds a bit much to me, tbh, even if it's an acceptable one - and remember that the horse treats are a much bigger portion size than a typical rabbit treat.
I'm sure the horse biscuits are safe for occasional use; all that's really in them is wheat, carrots, apples, and molasses. That's not worse and in many ways a bit better than many of the rabbit treats on the market. However, daily feeding would have me concerned; looking at the nutritional profile, a few things stand out to me:
- Molasses is high on the ingredient list, and carrots/apples are both sugary. AAFCO doesn't require labeling sugars in pet food, but I'm guessing this is pretty sugary.
- The biscuits have more than double the % fat most commercial adult rabbit foods.
- Calcium and phosphorous are also a good little bit higher than they are in most rabbit foods. Rabbits can get urinary sludge from things like high mineral content easily, so again: daily feeding would worry me.