Unfortunately, once a dog bites... it's likely to happen again. We (my parents and my siblings) had a dog for about 18 years, it never tried to bite any of us for 10 years, then one day he bit me... and slowly 1 by 1 he bit all of us in the family! The dog was always kept outdoors (this was how he was raised from day 1) so we had to keep him caged (it's a HUGE outdoor cage) if we had any friends/family over b/c we didn't want to risk him biting any one else. Of course, it's possible your dog may never bite again... but is it worth that risk? Your son could have been bit around his eye, mouth, or even his entire ear... causing permanent damage for life. It sounds like your in laws are only showing concern... sometimes babies and certain dogs just don't mix, especially if these animals have become a custom to a home with no children over the years. The only other option to ensure your son doesn't get bit anymore is to not allow him on the floor around the dog (which could potentially delay his physical development), or keep the dog caged when your son is roaming around (which wouldn't be a very productive life for your dog if she has never been caged). I know it's a hard decision, but ultimately you have to do what is best for your son. We had a dog about 4-5 yrs ago... my daughter loved him, but he began to chew all her toys to pieces. He was also so large (compared to her) that he'd constantly knock her over. It was becoming a hazard for our daughter, and we were having to keep him in his cage more often than not (which wasn't fair to the dog either!). So, we decided to put an ad on Craigslist and explained that we would give the dog away for free, but in return we wanted to know as much info as possible about your family, home, schedules so we knew our dog would find a happy home. After about 50 calls (or phone interviewing I guess you could say) I found the perfect home and I know to this day he is one happy dog.
Here are a couple great articles for children/dogs. Maybe it can help you determine what you can do w/ your dog. It sounds like maybe your dog has some confusion w/ dominance and thinks it's a higher rank than your baby? According to the article, predatory behavior can increase as the # of dogs in a family increase too (you did say your husbands dog was in the picture as well... so this might explain a little bit too). Hope thise helps some to see where your dog might be coming from, and maybe help to re-train your dog and re-establish the order of dominance... and it does ask a few questions to help the reader determine if the dog is safe around a baby based on past behavior (obviously the current behavior proves your baby is not safe at all at this point, but past behavior in other situations may have shown these aggressive signs as well).
I've been a veterinary technician for over a decade. I personally would not keep the dog any longer. You have to disclose that she can't be in a home with small children. I know you love her very much, but it isn't safe for either of them. She probably reacted to something that your son did. Grabbed her tail, pushed on her back, crowded her space, whatever. But you can't put your son in danger. It was bad enough now, you can't wait for it to happen again, because it could be worse.
I know it's heartbreaking, but a compromise of keeping her separated from the family wouldn't fair to her. She doesn't know she did anything wrong. The best thing for all of you is to find an older person or a family with no small children who will love her for the rest of her days.
I'm glad your son is OK. It must have been terrifying for all of you.
Unfortunately it is very likely that the dog will continue to snap at the baby. I also have been a vet tech for many yrs (about 15) and smaller dogs tend to be less tolerant of kids in general. I do believe with proper training and lots of work and supervision on your part you may be able to make it work. But I would NEVER trust that dog again around your child. My dog has never shown an ounce of aggression towards me or my 1 yr old but I dont give him an opportunity to harm her. He is too large to take that chance. He's 107 lb bullmastiff. When she is on the floor he is baby gated in a different area or in another room behind a closed door. If they are on floor near each other I am right there with them. Why leave room for an incident to occur? I know if he ever intentionally hurt her, he would have to go. And he understands his place in this home. He is not allowed on furniture. He doesn't beg for food. He's not even allowed in same room when I'm eating or preparing food. If baby is trying to get by him he is told to move. You need to either hire a trainer to work with you and show you are doing everything you can to make this work or get rid of dog. Things have potential to just get worse. Wait til your son is walking and running around... I'm sure then he's really going to test dog's nerves. I know this is really difficult for you and you say they are both your babies but reality is you really only have one baby there. I know the dogs are like members of the family and you love them very much but your son MUST come first. At least if you try trainer first your family will see you are trying to do something about situation to fix things. Good luck to you.
Over the past 3 months in the news, two babies have been killed by their family dog and one severely hurt (newborn). It becomes much more dangerous once the child starts to move around. I know you love the dog, but of course you love your child more and I really wouldn't take the risk.
You definitely have to do what is best for your son and if there is a chance that he dog could really hurt your son you can't have the dog around him. But-- We had the same problem with our dog when my daughter started crawling. Before that, the dog loved the baby, but when she started crawling the dog felt very threatened because the baby could now get to her and pull her hair, ears, etc. Luckily, our dog is only about 5 pounds and even when she tried to bite, she never hurt the baby. This happened about three times while the dog was getting used to the changes that were going on around her and now everything is fine. It is a big change for the dog, so maybe if you just keep them seperated except during very supervised interaction for a while the dog will warm up to your son. Now our little girl and our dog love to play together and our little girl has learned how to be really gentle with the dog. Just throwing a different viewpoint out there, but obviously if the dog continues to have agression towards the child it isn't worth the risk. Like I said, we didn't have to worry about our dog really hurting our little girl, but you could see how the dog responds to the baby in a very supervised setting and see if you still see aggression after a while or if the dog seems to be adjusting to the baby well.
i am so sorry you had to expierience this. i would say your only other option would be to keep your dog away in a kennel or fence off your yard for a small dog and make sure you put her away when the baby is outside. hope things work out.