If you just want to give the chicken wings to keep the anal glands clear - then once or twice a week will be fine. I usually give Alfie them when we have roast chicken, I just snip them off before I roast the chicken, giving him one then and there and saving the other till the next day. Giving two tends to make his poo a bit too firm and its painful for him to pass.Its trial and error really, what works for one wont work for another, some dogs become constipated, others get the trotts
If Barney has finished teething then he will manage a wing no problem. If his baby teeth are still there then bash it up with a rolling pin first. Some owners like to keep hold of one end if their pups are gulpers. Never leave a pup unattnded with a wing or rawhide - just in case.
As for salmonella, Im certain that Ive read of dogs getting it BUT to be honest Id be more worried about getting it myself - hence I feed wings in the garden. If you know your chicken is from a good supplyer then you should have no problems - I buy organic, which is why Alfie only gets wings when we have chicken ourselves