You can examine your full inventory and sell birds in bulk by tapping on the ‘View Full Inventory and Sell Birds’ button located on the bottom right side of the screen and once this is done your entire bird inventory will be displayed. Tap on sell mode and tap on the birds which you’d like to sell. Once you’re satisfied with the selection tap on sell to confirm this action.

Game will ask you to confirm this sale and will show the total amount of resources that you will receive. Tap the ‘Sell’ button again in order to confirm.