First heat advice needed...

Our 7.5 month old Toller is in her 4th day of heat. I have been walking her, but taking a walking stick in case she attracts some unwanted attention. So far no one seems at all interested.
Our breeder says I am going to get bit that way; a male isn't going to care that I have a stick. (I also have a karate black belt, but he won't know that) She doesn't walk her dogs for 2 weeks, and keeps them crated whenever they are in the house because she is concerned they will find a way to escape.

This is a completely new experience for me, but her advice is rather more extreme than what I have read on the internet. I don't think any of that confinement is going to make for a happy dog, and really don't want to do it.

We have stopped letting her out into the fenced back yard alone and have started leaving a leash on all the time.
Unfortunately our older dog goes in and out the front door fairly frequently, but we are going to put a fence in to block that off. I am thinking of also clipping her leash to something whenever the door will be open.

Any advice on these issues would be appreciated.

put her in a car and take her somewhere ,ie a park, to walk her. That way you won't have here scent trail coming from/to you house to attract randy males weeing all over your property frontage

People have different opinions on it, personally I walk my dogs as normal but rarely bump into anyone over the woods.
I currently have 3 entire females and 1 entire male plus 3 neutered males, I don't separate them, I watch them. I have never encountered a rampant male on a walk let alone been bitten by one. I let them out the garden as normal. Depends where you walk and what your fences are like I guess.

We had a fence put in, but the maximum allowable height is 4' so that isn't going to keep anything but terriers out.

My breeder says they run a 21 day cycle, and we are on day 5. So far absolutely nothing has happened. No dog has looked at her twice and nothing has shown up on our front lawn even though we have been taking her there to relieve herself. (the backyard is fenced and we used to just send her out, but doubt that is safe now).

Is the absence of any activity a good sign, or is it too early yet?

I gather you don't think the males are as dangerous as my breeder seems to think?

Thanks.

No I don't, I've had entire males and females of various breeds over the years and never had a problem. Others seem to report all kinds of issues. True a 4 foot fence is next to useless as you say, my fences are 6 foot with 2 foot of trellis on top. Different bitches will be receptive at different stages in their cycle, and until they are receptive they generally won't tolerate attention from males. So you end up only needing to be vigilant for about a week. It probably is too early yet.

I was told that a male might maul my dog if she wasn't receptive. Obviously not your experience.

Went for a 3 mile walk today without seeing a single other dog. Interestingly, it was the best behaved walk we have had. Maybe some good will come out of this.

In my experience any male pushing his luck with a disinterested female is likely to have a very angry female on his hands.

You could potentially be bit, a very driven unknown dog, you can be bit by a strange dog for coming between that dog and a resource for sure. It's probably not very likely, it depends on how well they back off to a human. I tend not to walk mine in area where there are loose dogs to be on the safe side, but in general I gaffe taken them for walks / out in heat.

Mauled? Maybe but doubtful, think the male is more likely to be mauled by the female if she isn't receptive.