how much Alfalfa Hay cubes should I feed to Bunnies?

I have two bunnies and I bought some Alfalfa hay cubes today for them. How much of it should I feed to them. I gave them two small cubes this evening. I just don't wanna give them too much or too little so any advice on this would be great.

Alfalfa cubes can be fed as a treat to rabbits, I woud say one maybe two small cube/s a day. Im not sure if you are giving the cubes as a treat or as a feed. It is best to give the bunnies a good rabbit pellet high in fiber (18% is ideal). I feed my rabbits Heinold, but you can also find some really nice pellets at your local pet shop. Oxbow Hay Company and ZuPreem make real nice pellets, however they can be a little pricey. Ideally you want to stay away from pelleted diets that have "cereal" grains and colorful bits of junk in them. I personally dont like Hartz, Kaytee, Vita Kraft, or Sun Seed pellets. You want to stay away from rabbit treats with grains, nuts, and sugars as well. The best thing for rabbits it a good quality pellet fed in the correct amount of 1/2 cup a day per 6 pounds of body weight (at adult hood). Young bunnies are free fed pellets until they reach adulthood at 7-12 months of age. Good quality timothy hay is free fed at all ages and alfalfa hay/pellets are ok for young guys but need to be monitored in adulthood. Alfalfa is high in protein and can lead to fat rabbits. Also, rabbits can have up to 2 cups per 6 pounds of body weight of fresh rabbit approved veggies a day at adulthood. Starting them out slowly at a young age until they get to maturity.
They can have small amounts (2 tbsp per 6 pounds of body weight per day) of fresh fruits like apple, pineapple, pears, peaches,blueberries, raspberries and strawberries.

Hope this helps! Here is also a link that might help you:

http://www.rabbit.org/faq/sections/diet.html

It's only as a treat I am feeding them a very good brand of rabbit pellets.

Alfalfa cubes are too high in calcium and will cause calcium buildup in the urinary tract, causing serious problems down the road. But, this is generally only a problem if you feed them on a regular basis. I would suggest buying a bale of good quality grass hay, prairie is what I'd recommend, either that or brome or timothy. A bale of high quality prairie hay costs me $3 and lasts...usually around a month. My buns are spoiled on fresh grass, they tend to snub their noses at 'that dry stuff'.

I do feed alfalfa as a treat, however. My young bunnies get 1 cube to chew on per week, my older bunnies the same. I also let my bunnies 'free range' as much as possible. I keep my youngsters, not old enough to breed or weanlings, in my chicken tractor. There they can get up and out of the weather, or go down and eat fresh grass. My older breeding buns get a nice big cage, I'm planning on modifying it this week so they can better get to the grass. Usually the cubes go untouched, but it gives them something to grind their teeth on if they want it.

For treats, try melon rinds. My buns just about maul me when I come with melon rinds. Or apples, pears, that sort of thing. I usually give them whatever veggie scraps I have too. They die and go to heaven over cucumber peelings

My mini rex don't even each eat one a week. They are a good backup food to toss in the cage but a good quality grass hay would be much healthier and more appreciated. They only eat the hay cubes if they have no other choice or nothing better to chew on. Half of them will choose cardboard over hay cubes.