Welll, call me insane, but i woke up yesterday and decided to push for it, totally f2p of course. I barely had any fat chickens ready, and didnt have much of a stockpile of regular chickens either.
Started day with only 12,000 points. Grinded all day, scored about 30,000 from soulstones by selling some souls to trade for 2 big ones (got me a 6-star Bad El woot woot.
Finallty claimed Alatreon, it cost me roughly 1800 gems in energy, although i completely depleted my misery shards down to less than 40. And used about 300-350 brews of each color.
All in all, porbably worth it, 6-starred 3 people, I got enough chickens ready for another 3 when i want to rank up new ones. One-day intense grind, veruss a 14-day grind for a fusion. Not bad. But, granted, i did waste a whole day doing this.