Not too young. Feed ad libitum at this age. Mine is 3 months old and he’s quickly eating more than 10 crickets, but it depends on the size of your feeders. Just make sure they’re appropriately sized for him and your gutloading them first.
My juvenile is on crickets as well, but are not the best feeder due to their phosphorus/calcium ratio. I’m introducing him to BSFLs and roaches I got from @jamest0o0. You’re going to burn through 100 crickets pretty quick.
Josh’s Frogs. Crickets and BSFL. @jamest0o0 has roaches I’ve ordered and I haven’t had one die off yet ? well except for the few who have met my chameleon.
IMO this is a very grey area and know one really “knows” what is safe or not safe to give. I’ve heard people on both sides of the spectrum that have successfully raised chameleons on either no supplemental D3 by just using proper lighting and also others who supplement 20,000 IU/lb of D3...
1. I think most will agree any time is fine to upgrade. I have my 3 month old in a 2x2x4 already. I can’t ever find him when he’s not basking, but he seems to like it.
2. I don’t do bioactive so not sure on this. I would guess another type of insect could help here that will eat the gnats.
3...