I'm presuming those are 8x5 inches? In any case I'd try and give my stick insects a larger enclosure, regardless of how ever many animals are inside.
Afew years ago I kept and bred thousands of Indian Stick Insects (the common sticky) and had about 5 to a medium plastic pet cage I bought for £5 from my local pet shop. The insects will wander all over eating the roughage you provide them so it may be best to give them that extra bit of space. Off course, this is my opinion and is no way a factual input.
