@Graceface thanks for the tip!
Update: Midway through their second week. Their numbers have dwindled to 19 by my count last night.
There's 3 on the big free range plant and the rest are in habit containers. Most sharing the space.
I tried to keep as many fed as I could but food became an issue early on with so many as well as proper housing space and time as well. I've literally put in a few hours a day just trying to make sure some of them are eating. I bought up all the fruit fly vials at my local petstore so I feel there's finally a good ratio for the mantids still alive to all eat.
I have seen a few instances of cannibalism, which are sad but welcomed. At least I know the victim's death means nourishment for it's sibling.
Although I'm sad for all the ones that didn't make it I am trying to allow nature to take it's course. Survival of the fittest. In nature how many from an egg survive to adulthood?
Two examples of this:
Dropped a fruit fly on a leaf for one nymph on it. Struck at it four times, kept missing/knocking it away. FF climbed over the edge of the leaf to the underside. Damn, I thought. I didn't want to lose it. Looked underneath the leaf. Another nymph was already under there waiting. Not only did it grab the FF on the first try but it lost it's footing, flipped through the air and landed on a lower leaf. Still hung on to the FF. Impressive, I thought. That one earned it's meal.
Tried feeding another nymph on a vertical standing leaf. Had FF hanging onto the surface of a business card. Nymph was eyeing it up, taking it's good ole time to get positioned right. All of a sudden, little head and shoulders appeared behind it poking over edge of the leaf. Another nymph that was on that backside and took notice. Sneak attack. Stole the meal. First nymph looked at the other like "bro... You just stole my dinner." Then walked away in disappointment.
One thing that's tough is I like to have substrate in the habitats so it feels more natural, but it gives more places for the FF to hide. I'm doing things to circumvent this though. One thing I have that's really effective I call my feeding jar. Drop a nymph and fruit fly in it and it's a small jar so very easy for the nymph to get it's meal quickly. When it's done eating I swap it out for another.