Its always best to find someone you trust who can come over everyday to check on them and feed them. Since you arent going until August, you would have time to get one of your "trusted" friends to start coming over to learn how to care for them.
Make up enough food for the entire time you will be gone, freeze each meal individually and put the date on each. That way, whoever watches them can reach in the freezer and pull out their meal. This would also be the "only" time I would suggest putting a bowl or two of dry kibblein their cage. "Just in case".
You might want to also consider putting ectra water bottles in their cage "just in case". We normally suggest to always have 2 water bottles, but I would put 3 or 4.
AND call them everyday!!!