What Are The Signs For Starting Potty Training?

There aren't really sign's. You start ASAP. Many breeder's will start with something like pads around 3 weeks or so and before the pups are old enough to go outside and once a new pup comes home it should start immediately, again safety is an issue and a factor as you do not want them where other strange dog's may have been until they have finished their puppy sets (usually around 4 or 5 months) of shot's as they are still high risk for catching something and parvo in particular. Here's some basic's I wrote up for training.
Basic crate training ALWAYS applies. The pup should never be out of your sight unless in their crate and then they pretty much have no opportunity to misbehave or go in the house. In order to teach a puppy not to do something you must catch them in the act and be there to praise them when they've done something right. It is also a bit of an incentive to hold it because if they don't they've just punished themselves. For potty training purposes the crate space is just large enough for the pup (enough room to stand up, turn around, and lay down for potty training, once that accomplished 100% it can be whatever size though if you slip up you may have to revisit the smaller size). If it's too large they will be able to go in one area and sleep in another and isn't effective for that purpose (and this goes for large spaces and free ranging too). The crate is NEVER a punishment, that is their security and their safe place, it's THEIRS. It is also a play on their natural instincts (what I call hard wiring) as they are domesticated den animals. Ever noticed how many dogs like to sleep under a desk, or bed, or against something if something that makes them feel enclosed is not available? They feel safer that way and it can also help with confidence. Leave the door open when you are just hanging out. You'll find they go in there to sleep or when they are uncomfortable or for tons of other reasons. I have one dog in particular who tells me he's done something he thinks he maybe shouldn't have by going in his crate. If he's in the crate he can't get in trouble.  I can tell by the look on his face, LOL. Also, never call your dog to you for punishment. You will likely inadvertently discourage them to come when called.
Best results are to take them about every few hours whenever you are home and available to do so as young pups with longer periods between as they get older. You stand a better chance of catching them when they have to go :-). When you see the signs your puppy's going to go (sniffing, circles, whatever) you are going to say 'let's go potty outside (or whatever words and area you have decided on) and get them there and when they do go outside tell them what a good puppy (very excited, they just did the best thing in the world) you just went potty outside (or whatever they've just done that you told them to do). You can definantly feel a little silly but it gets a great response from them, they've already learned that tone is a good thing so they connect it quickly and then the words and action. Your dog should work to please you because it makes you happy and therefore them, never out of fear, and using treats makes them work for treats and not you (too many treats can upset their bellies too and even throw off their diet sometimes). So those are in moderation but can be used. Praise is always available and the thing your dog wants from you the most. Always use the 'command' words as often as possible (provided it's what you're working on) so they learn them faster and one word means one thing. Tell them what you want them to do and once they've done it they are just the greatest, smartest, cutest in the whole wide world because they _________. One they begin to go on their own, KEEP PRAISING. You've done a good job with letting them know what you want but it still has to be worth it to them. Any time you see your dog do something you've trained them (or are attempting to train them) to do they should still get a good dog, its continuous positive reinforcement. Even if you did not just tell them to do it. If not, why continue? Accidents? Well, you can stop them if you don't get there soon enough and they start to go. More of a "No, you go potty outside" in a firm voice. No yelling or spanking. Pick them up and then continue with normal procedure. If you all of the sudden find it that's your bad cause you weren't watching and it may be past the point for them to remember. They also don't have much bladder control and can't help it until around 4 or 5 months usually so mistakes are often the fault of the humans involved. Small dogs usually take longer due to their smaller bladders :-). Also frequent/small/excessive urination can sometimes indicate a problem that needs treatment from a veterinarian so it's important to watch for things outside of the normal. Puppies get urinary tract infections too.
Puppies have a VERY short term memory.  10 minutes later and they might not remember what it is they've done that's upset you so badly. That's why catching a puppy in the act is key and essential to training. Their memory gets better as they get older. Example: You take a shower and leave your puppy out and unsupervised. As soon as that door is shut they get your shoe. 20 or 30 minutes you come out and probably are upset. Yelling, waiving around the shoe, anything else is VERY scary for your pup. They don't remember what they did. You just look like a madman who is now unpredictable and to be feared since you just started yelling and waiving that thing around and they have NO idea what it's all about because they can't connect it with something they did. They do remember better as they get older (which is why older pups are often much easier to train AND you may have jumped a lot of the immune system hurdles).
Every person in the house needs to have the same rules and the same commands for the same thing. One word means one thing. Otherwise they get confused and you guys end up frustrated. Sometimes a family meeting helps so everyone is on the same page :-). Example: Someone comes in my house and my dog has just jumped on the couch where they want to sit. What's the most common thing they are going to say? Get down. WRONG. They just told my dog to lie down and lay down only which is the opposite of what they wanted. It's off or move. NOT down. If down meant two things the dog is never sure WHAT you want and may end up doing any of the things it can mean OR nothing because they are confused.
Let your puppy become comfortable on a leash when you're not actually trying to make them walk since pulling can damage the throat. Be sure to find out if a collar or harness is best for your breed.  Just put the leash on when sitting around. You shouldn't take your puppy out until after the last set of puppy shots has taken affect anyways, as they may still be at risk. Depending on the pup's own immune system only one of those may work and you don't know which one or when unless you are running blood tests to check the titer levels, much simpler to be sure to do them on schedule. It is usually every 3 to 4 weeks (from 8 weeks though sometimes a parvo vaccine may be done around 6 weeks)  until 4 or 5 months and rabies can be done around 3 to 6 months the first time depending on where you live and the regulations. It is often one of the LAST sets that does the trick so be very careful and nothing is 100% guarantee. After they are comfortable 'tethering' or the 'umbilical cord' technique can be very useful. This is when your puppy is attached to you by a leash so they are never out of your sight and getting into trouble, lol. It also seems to help with establishing who is the boss :-). I've tethered many a naughty puppy and the results are usually very good and very quick. Training sessions for ANYTHING should be very short for a puppy and usually around a 15 or 20 minute duration. Anything more is too long for them. If you are 'tethering' then you can make sure it is more relaxed.
Learning to walk. After your pup is comfortable being on a leash they do tend to follow you around a bit and it isn't much work because they weren't traumatized by the introduction to the leash usually :-). To work on walking put the end of the leash in your dominant hand. Run the leash behind you and the puppy is on the opposite side. This way they CAN'T pull ahead of you because the back of your legs or knees will be in the way. They learn to stay with you. If the leash is longer hold it so the length is just long enough to keep the puppy at your side. If they start to misbehave or pull, STOP. Tell them no firmly. Say heel or walk or whatever command you've decided on that means to walk with you (at all the appropriate times.  If you don't walk politely, you don't get to walk. Misbehavior interrupts the fun. Be sure to praise your pup ANY time they do something correctly and let them know what they did using the word that means to do it. Treats in moderation :-). Example: (yes I know this is walking but) SIT: Butt touches ground (in the beginning and after that they must be actually sitting). You know the voice ;-) and remember to be enthusiastic. -Oh!  Good puppy! You sit. Good puppy. What a good puppy to sit. Good puppy – They learn what the word means to you and that word in conjunction with that action gets them plenty of praise and they WANT to do it pretty soon (as soon as they understand what you mean). While you can certainly tone it down don't forget to tell your older dog they are good too when following a command. Yes I know I said that but it's important. If the dog is capable of overpowering someone they probably shouldn't be walking them. Period. Make sure your dog is chipped and registered to you in case they do get loose, it can be a huge help in making sure your dog gets back to you in case of an accident.
Diet is important for a growing puppy (meaning contents, a high quality food is always important for any dog with many benefits to us including that they are healthier and look better, less stool, less shedding, fewer allergies, they look better, they are healthier cutting down on trips to the vet and many other things) and different breeds need different things. Look for a five or six star rated food on the analysis site and the reviews can be very informative as well.  Dogs prone to bloat especially should be fed several small meals a day and exercise and water intake should also be monitored closely for about 20 to 30 minutes before and especially after each meal for best results. Many very small breeds may do better on a higher protein (and other things) diet as they tend to have a more difficult time regulating their blood sugar. Nutri-cal or Nutri-stat is a must! Breeds prone to dysplasia do better on a lower protein diet (around 24% or so) is good to help prevent accelerated growth and aggravating those issues in conjunction with proper exercise and activity and activity level (Do not overwork your dog).
So those are some basics without being breed specific and gives a basis for most training. And it's really not as hard as it sounds and any work put in is well worth it later for you AND your pup. Sometimes just when you think they have it down you have to go back to basics (and sometimes because you slacked off). Good luck.

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