Clean once a week or as necessary based on your population density.
Feed a lab block like Mazuri, OH Kruse, Volkman, etc.
Remove weanlings at 4 weeks old.
You won’t have a hard time sexing them.
I worm once a year, otherwise, just keep an eye on hygiene. Rats that keep themselves clean are healthy, dirty rats have something going on usually.
I share a lot tips in this thread
For euthanasia, you need to use a CO2 regulator with a flow meter. If you’re not measuring the flow of gas, you’ll suffocate the rats instead of humanely euthanizing them.
This is the AVRMA guide to humane euthanasia
Within the guide above you’ll find a formula for calculating the correct flow rate per the size of your chamber.
A chamber can simply be a large gasketed snap top tub that you poke a hole in and seal the gas hose into.