Dream Zoo after 30 days

I'm actually not sure how many days I've played, but I've been playing everyday since I got the game and I got this Goal last night. 30 days consecutive played days. I'm Zoo is currently at level 48.

However, I find that I am somewhat plateauing. The game has somewhat become stagnant.

Due to the success of my Dream Zoo baby placement. My babies are getting birthed at a super high rate. Visitors are coming in and accelerating my babies super fast. This leads me to a (good?) problem. I can't get Hearts or Coins fast enough to keep up with baby production.

Although, I did waste a whole bunch of hearts just breeding gazelles, zebras and giraffes. I thought that the rate and the low cooldown timer would give me a lot of coins. It did initially since upgrading ranks of animals were somewhat cheap. However, upgrading animals costs upwards of 400,000 coins. I should have gone with more cheetahs. It seems Cheetahs cooldowns are more inline with how often I check the game.

My Army of Gazelle

Ever since my Dream Zoo has started experiencing problems with visiting friends' zoo, I can't go to enough zoos per day to get any good number of Hearts. I actually resort to getting the bulk of my hearts from gifts from friends. This is a good motivator for me to send Hearts as Gifts every day to friends. This is in the hopes that they return my gifts with hearts.