freshly hatched mantis are pretty small for even an adolescent cham, there is not much to them. it would be like using anorexic mosquitos as feeders.
why not just raise blue or green bottle flies? they are super easy to raise and you can have 1st generation flies in about a week. they are probably one of the all time cham favorites, which makes them an excellent strike breaker.
how long mantis take to hatch depends on species/ooth temps/ storage etc. i get my chinese from the local garden store for $5 ooth. they just leave them out in there shop and whatever ones dont get sold in time just hatch out into the shop. i have actually had them hatch out in the car on the way home from the garden store lol.
cf member colorcham427 sometimes has mantis for sale.
anyone seeking mantids of any kind are strongly recomended to try the classifieds of
http://mantidforum.net/forums/
you can usually find anything mantid there, even rare ones if you are not in a hurry. you could place a wanted there or just subscribe to the classified thread tag you are interested in and you will recieve an email when somebody posts what you are looking for.
there are some truly smokin deals there. most mantids can be found for a fraction of commercial mantid places. winter before last , i got 7 orchids for $40 shipped, from a lady username katnapper, (i dont think she is doing it anymore) thats like $300+ elsewhere.
mantis are truly great pets, the only problem with mantis is that by the time you get super attached, they die, so if you dont get an ooth to show for it, it can be a real bring down. i never did get an ooth from my orchids, and it was a real heartbreak when they all eventually died 1x1. i probably wont do orchids again unless i can get really serious.
orchids are truly beautiful, like a ep said, "the pink aliens"
youtube has a lot of really great mantis videos, a couple of my favorite examples of just how beautiful hymenopus coronatus can be;
http://www.youtube.com/watch?v=pL7BTkh3gHU&feature=related
http://www.youtube.com/watch?v=pL7BTkh3gHU&feature=fvst