Normal puppy behavior or something worse?

Recently adopted a border collie - pitbull mix from a rescue. He's about 6 months old now.

We've had him for about 2 weeks now...and some issues are starting to arise.

He started off perfect - nice and quiet, obedient and sweet. About a week into having him, he started exhibiting weird behavior. At night he has spurts of energy, unwilling to just lay down and go to sleep when we do (he initially had no problem sleeping when we did). He runs around the apartment gnawing on sheets, humping sheets, and biting us (more on this below). He may very well demand more exercise during the day, but because he had leg surgery a few months ago (was run over by a car) - we were advised to lay low with him for another month so he can heal up even more. We still take him for 3 - 4 walks a day around the block which should be fine and we're still playing minor games with him inside - such as tug of war, so not sure if this is the solution.

Also, he has begun frequently begging to go outside. He claws at the front door and whines, even after I've just taken him out to go to the bathroom. When I do take him out, he doesn't attempt to pee/poo. It's like he's hunting for some entity that he "knows" is out there somewhere, if that makes sense. And when we're out on a leash, he is constantly looking to eat everything that moves - this is probably just a typical puppy thing that he'll outgrow right?

Lastly, he has begun nipping and biting us a whole lot more while playing. He is OBSESSED with biting our hands, thinking that we're playing with him. We have tried everything to curb this - yelping, "NO!", puppy time-outs in another room - But nothing seems to work. Any pro tips on curbing this fast? Or is this just something he will out grow?

I am pretty much just wondering if this is all normal puppy stuff that he will out grow, but any tips will be much appreciated.

Thanks in advance!

Him not being allowed out too much because of his injury may well coincide with the horrible teenage months.. Is he neutered? There might be a bitch in heat around that he noticed..
About the biting: has he lost all his puppy teeth yet? He might be looking for things to chew to ease the teething. Give him enough to chew, toys, chew bones etc.

Border collie - Pit Bull cross.. he's going to be an energetic lad

Thanks for the reply! Yes, he is neutered so I don't know if thats a cause. And he only has his adult teeth now - no more puppy ones. He has PLENTY of chew toys - ropes, bones, kongs, plenty of options to soothe his teeth but he just loves our hands...

Hi you can put him out of the room when he is acting weird,not for long,but if he starts acting up do it again,he will soon get the message,with biting hands stand up and dont say anything,or you can place him on the floor,the best thing to give him is kongs they keep them occupied crystalgirl

Sounds like puppy behaviour and energy to burn.
Keep it simple,
Reward good/wanted behaviour
Distract unwanted behaviour and replace it with a game or training him a wanted behaviour.
Keep all training upbeat and happy

Are you sure he is only 6 months I'm almost certain they don't stop losing puppy teeth until almost 7/8 months may be wrong,if he is biting your hands distract with a chew or toy put your arms on chest & your back to him ignore him if he catches your hands yell out & say ow loudly keep doing this he will/should get the message it's not acceptable behaviour tripe stuffed chews are very good keeps them occupied for hours if you can get them, sounds like he is literally stir crazy he should get better once he is allowed to burn off that excessive energy, once his leg is healed, good luck & I hope things improve.

sorry Shane cross posted

Does the rescue you got him from have a trainer/behaviourist who can help?

It's far easier to show people how to respond to mouthy teenagers than to try to explain in writing and someone experienced who can observe what's going on will be able to put your mind at rest or otherwise and offer invaluable advice.

In the meantime, control your games with him. Mouthing means all action stops (often a split second will get the message across). When action stops, you become a statue, don't look or talk and resume the game when mouthing has stopped. When playing tug, make sure that you train a 'give' so that you can stop the game as well as start it when necessary.

Introduce some training into your play sessions. Leave it and stays are great self-control exercises to teach.

You have a very, very active cross on your hands who is having limited exercise so some boredom and frustration will be coming into play.

It sounds like normal puppy behaviour and you have two very intelligent high energy breeds there so he's going to need lots of stimulation and exercise...I understand you can't do the exercise at the moment.

Have a look at
http://www.apdt.com/

And see if there is a puppy class in your area, I think clicker training would be really good for both of you and it will tire him out in, which it will be great especially while he is in limited exercise. They also have some good tips on there too.

Oh and in the evening spurt of energy thing...my staffie used of do that and wouldn't settle until I cuddled her into submission and she finally fell asleep. Lol. She would wriggle and then couldn't resist snuggling under me chin and would soon be snoozing.

It would also be an idea to get lots of brain testing toys like kongs, buster cubes, and nina Ottosson puzzles.

Sounds like perfectly normal puppy behaviour to me. We had a very mouthy boy and we stopped the tug of war games. We play fetch etc., but we do not do tug.
As for the mouthing he is teething and even when they have their adult teeth they have to settle into the jaw. Find a command or distraction that works it may take some time to find it but persevere till you do then continue to use it and make sure all family members us it too. It will cease eventually.
As for the not settling at night they are like naughty over tired children and I think you need to step in and settle him down turn the lights low etc., and hopefully he will understand and start to calm down.
As for the wanting to go out he is not getting the exercise he needs due to his recovery from his injury but of course he does not understand this so wants to get out and explore all natural behaviour do what you are doing plenty of gentle games and distractions.