We have a 5 year old golden doodle who has been wonderful. She walks around the yard off leash always with us several times a day to do her business and walk around. She knows the yard boundaries. There is no way to have a fence in the yard (HOA). We have not needed it either. She follows commands of come and sit and stay, go get things, go find people or objects in the house, right and left hand, etc. Really likable and pleasant dog. We walk with her on leash 4 miles a day usually in the evening. There are lizards and rabbits that interest her but not the deer. She is motivated by rewards of food and praise and ear rubs.
Here is the problem. We live in a suburb that is rural. This morning a herd of deer were outside the back door I did not see. I opened the door to go out with her to do her morning business. She took off after the deer (protecting the yard and prey instinct?) and they of course ran. She went into the wooded area behind all the houses and I lost her for several minutes. She did not come on command. She came back to the house and one lonely deer was still behind a bush wondering what happened to every one. Our dog then did the same chase and I lost her again.
Now, the rest of the day with outside time was normal. Come time to walk, she has her leash on, we get to the street and she she takes off to the wooded area again for several minutes. She has broken the taboo of leaving the yard. Nothing that I can think of has changed other than the herd of deer.
Ideas? Training material you like? Equipment you like?