Crackers aren’t good for buns, but a piece won’t do any harm.

I agree with LBJ10 – crackers aren’t good for bunnies. I’m sure that if your bunny ate a little, there wouldn’t be too much harm. My bunny has accidentally taken nibbles of chocolate and biscuits, and he’s unharmed. If I were you, I would monitor your bunny, and if it’s eating habits change (i.e stops eating) get it to a vet immediately.

Again, a small amount wouldn’t do any harm

Rabbits are very good at begging for food it they see a human eating something. My bun goes crazy when he hears me eating something crunchy like crisps, cookies or knäckebröd. He immediately starts to beg and vacuuming the floor for crumbs. A few crumbs wouldn’t do a bunny real harm. The actual problem is with starch, sugar and other carbs. These can for instance be found in grains, fruit and the orange part of carrots.

Rabbits are on high-fibre diets to keep their gut flora balanced. Feeding them starchy or sugary things regularly will promote overgrowth of harmful bacteria in their gut. This causes gas, mushy poops and sometimes even leads to potentially life-threathening GI-stasis.

This is the reason why fruit and small slices of carrot should only be given as a treat. Feeding rabbit food that is a mix of several types of kibbles is also discouraged, because it often contains a lot of starches and grains. It’s only made to look appealing to humans, but plain high-fibre/low grain pellets are way better for buns. These little fur-monsters tend to be picky about food, and they sift out the tastiest bits in the mix and leave the rest. Rabbits who do this often get way too much carbs, leading to the earlier mentioned gut problems.