Duo Spider 25 (easy-ish)
So I think I finally got it down. Takes about 3:30, but it works. UDK and Mordecai seem to be the team to do it. I'm still testing, but it seems UDK has enough heals to keep them safe.
I have my UDK built for Hydra to tank Mischief. So tank stats, as well as high Res. You need him to be tanky because he eats all the spiderling bites and have RES to not get Poison. Thankfully, his passive allows him to get tankier as the chickens die out.
Mordecai is just there to place HP burn, so Accuracy, Speed, and tanky enough to eat Spider Queen's attack.
If you have those two, it's a great way to level chickens and make silver.