Answer by Rory Young:
If you do as you have described a lion will still know how to hunt but may have some difficulty at first and I will explain why.
Firstly. They have a hunting instinct. They are pure killer. They have evolved to kill. They enjoy it. It is fun for them and they get excited by it. I can’t bear the Hollywood bs of lions only killing just what they need. It is so untrue. They are well known to kill more than one animal and even go on killing sprees as do other cats and hyaenas.
Secondly. When a lion gets hungry it gets nasty.You may have heard the saying “a hungry man is an angry man”. Lions are the same. When they get hungry they don’t just want to eat they want to KILL!
This strong urge to kill, just as powerful as their hunger, does not go until their belly is full. This is why killing sprees happen. They may kill one animal and then, before eating properly and satiating themselves, come across another opportunity and then kill again.
This is common with other cats too. There are numerous accounts of leopards getting into livestock and killing one animal after another. I remember an description from the book Smithers and Skinners Mammals of the Southern African Sub Continent of one leopard that killed 39 lambs in one attack. There is no way it was going to eat 39 lambs. Maybe two or even three but not 39! Simba would be horrified!!
Thirdly. There are also learned hunting and kills that they gain from experience and those do not go away. If your lion had never been in the wild these skills would not have been well developed and the released lion would then have problems feeding itself.
Lastly. Fitness! Just like one of us they can get fat and lazy getting too much food and not enough exercise. This is why I said they may have some difficulty at first. Not too much though! The instinct will still take over..
I love lions they are truly awe-inspiring animals! Seeing them hunt is one of the most incredible things you can ever see.