Puppies destroying our sprinkler lines

We have 2 puppies- 10 and 11 months. They recently have discovered our drip landscape lines irrigation heads. I live in a desert climate so drip irrigation is super needed for our plants. They are ripping them up and chewing them like gum. We tried spraying bitter apple spray on them but it hasn’t helped. Any suggestions for stopping this? We can’t watch them outside every second. We do have a kind of small crappy enclosure we put them in, but they can’t run or play in it. They have a ton of toys inside and out also. Help!!