Here um gonna show you how to feed an animal..It will help them grow easily..
Step 1: Gather Thier Favourite Food..
For e.g , Wheat for Cow and Goat , Apple for Horse , Seeds for Chicken..
Step 2: Feeding..
Simply Target them ( You need Split Controls Enabled in MCPE Options) , Agter Targeting them with thier favourite food , Hold your finger on the screen , You will see Hearts coming From them , They are fed and will grow Rapidly. If there are two or more animals , Feeding them will Generate a Baby Animal, It can be done with only one animal , but that will take a lot of feeds..