So i follow Pokebot.Ninja forum and someone posted a nice little trick to feed your pokemon in gyms with only a few berries
(You know, feeding a 3000CP pokemon takes alot of berries)
Make a few new accounts (4 or 5) and start harvesting berries on them (60+)
When you have enough, stop botting and use them to login on your phone.
Now when you feed your pokemon the first berry the heart fills up a great amount, when you feed a second and third etc... berry it only goes up VERY little.
The trick here is to switch account and feed the same pokemon again a berry with your second account, switch back to your 3th account and do it again.
this will only need 4 to 5 berries to fully heal your pokemon (depending on the CP.
Another tip:
Don't put 3000CP+ pokemon in gyms, the heart deplets 10% faster then a pokemon under 3000CP
So a 3000CP+ Pokemon gets it's heart fully depleted in less then 12h, while a pokemon under 3000CP needs at least a day or more to fully deplet.