Many on this forum raise caterpillars themselves. I use what was originally intended to be a reptile cage, but is used for caterpillar raising. There are hanging cages you could use, but there are many things you need to know when raising them yourself.
The cage needs some ventilation - although some people raise early instar cats in unventilated containers, I don't, so I wouldn't know how to advise you. Providing the cats with their host plant leaves is tricky, because the leaves need to be fresh, and keeping them fresh is best done in different ways with different types of leaves. I keep most of mine fresh with water, that is, put them in water picks or plastic left over containers with holes punched in it, so you can insert the leaves/small branches but not have open areas to the water where the cats might drown. Also, if you put the cage in full sun, the cats can fry if not given a good place to seek shelter from the sun. My cages are on my front porch, with strong light, but little or no direct sunlight. Direct sunlight tends to wilt the leaves also.
It's an involved deal to raise caterpillars. Have you checked the FAQ for info on this subject? Read that, and if you're still interested, we'll be glad to help you.
Sherry

Here is a link that might be useful: Reptarium

Sherry, thanks for the info - I'm new and didn't realize there was a FAQ on caterpillars - I will find it and read it right away.

The reptile cage is pretty much what I had in mind when I was thinking about building a few caterpillar habitats. I also have seen them in Galveston, TX at rainforest gardens down there. They have a giant enclosed and netted box on a wall and they have hundreds of caterpillars they raise and hatch where the public can view them. That is what inspired me to try to save/relocate the ones I have.

I love to research and read, so I'm on the look out for some good titles on rearing butterflies and would love to find a great identification/class/species type picture book (large book with great color photos) as well. If anyone knows of any great titles that they've enjoyed, please let me know.
Thanks!

I've been thinking for years that a small, cheap tent--like for camping--and potted seedlings that could be moved in and out of the tent as they're consumed, would be a fun, easy set up for Monarchs and/or BST. If the tent were in a shady spot and you kept all the "windows" open for ventilation, I would think the temperature would be alright. And both milkweed and dill are easy to grow from seed, and potted plants wouldn't dry out and wilt like cut leaves and branches. I really want to try it this year. So, I'm going to wintersow a bunch of Asclepias and dill. I'll try to give progress reports. Maybe a similar arrangement would work for rescuing cats in your yard.

Martha

When using a screened tent, remember the disease issue too. Be sure to disinfect the entire thing every month or so. A good dunk in the tub with 97% water and 3% bleach for 15 minutes should kill all pathogens.