How high a pen do I need?

Question
I have 3 (2 females and a male)bunnies that need to be bonded. 2 (female and male) are already bonded. Since they have not had any experience outside and the weather is beautiful I was going to try bonding them out on the patio. I am not sure how high of a pen I will need to prevent anyone from escaping. I will be there at all times but bunnies are FAST! The two that are bonded are a brother and sister. They are regular old spotted bunnies. They probably weigh about 5 pounds. I am bonding them to a dwarf female that is less than 3 pounds.
They have all been spayed and neutered. The last spay was a month ago.
I appreciate any tips you can give me.


Answer
Dear Kathy,

A bunny will not be able to quickly jump over a 3 foot barrier, so that would be a safe option.  You can find excellent articles with lots of tips for safe bonding here:

http://search.atomz.com/search/?sp-a=00062824-sp00000000&sp-q=bondiung&user=ente...

Hope that helps!

Dana