yes - animal corpses decay independent from where stored (house, boat, cart) - even keeping them lifted doesn't help against decaying
after first 8 hours skin will be gone, after another 8 hours meat and insterines, the bones will be gone in another 8 - 16 hours (not sure atm - i had 24 hours on mind for the whole process but elsewhere it is said 8+8+16 hours)