Frozen Gel Bottles for Cooling Breeder Buck

Would it be feasible to use the frozen bottles so the Buck doesn't go sterile in hot weather?

We use frozen 2LTR bottles for the house rabbits.

I have a rotating collection of frozen 1L bottles I use too. My rabbits don't generally get too close to them, they often seem to like licking them instead or even playing with them like toys (that said, my rabbits are adapted to the heat here, apparently, and even though I'm in Brazil we probably didn't break 90F three times this past summer).
I use the bottles because occasionally the rabbits will gnaw on them and 1) bottles are free and 2) frozen water won't hurt them if it leaks out and they eat it. I wouldn't use frozen packs.
Another thing I do that might be useful for you is to put either floor tiles or countertop granite or other stone in the hutches in the summer (I replace them with wood planks in the winter). These stay nice and cool during the day and the rabbits are always stretched out on them.

Marshall & Spud (RIP)

I've heard frozen bottles can be used ot keep the temperature down. if your buck doesn't snuggle it, a small fan can be used to blow air over it and cool him that way. I've seen where the air coming off a  'camping ac' that was just a fan blowing across a bucket of ice got down to 55 degrees fahrenheit, so it's potent cooling.

As a halfway point between gel packs and 2 liters, you could use PVC pipe to make polar tubes.

Our rabbits like to roll the bottles and lay in the cold condensation left behind.
We also make ice cubes with old deli cups like the ones sour cream comes in to keep their water cold.

They are so spoiled. Marshall will just sit in front of his water and pout until he gets fresh water & a new ice cube 🤣.

I was actually thinking about using quart mason jars. Of course I wouldn't fill them high enough to break in the freezer.

I figured there's nothing on a mason jar to chew. They're cheap, abundant and I can just cycle the same ones.