I don't have a dog because I can't be bothered to take it for a walk.
Walking the dog is a pain, so it's better if I don't have one.
日本語でよく「出来ない」「飼えない」とか言うんですが、時々そういう表現を直接英語に翻訳すると、ちょっと変な感じがします。「I can't have a dog」というと、「もしかしてどうしてもしたくても無理なこと？」と考えてしまいます。
そのかわりに、アメリカ人は「I don't have a dog」（ただの事実ですね！）とか「It's better if I don't have one」（ワンちゃんに可愛いそうだから飼わない方がいい）の方が使いそうです。
I can't have a dog because taking them for walks is too much trouble.
When you say "I don't have the time for a dog." a native speaker will normally assume you are referring to the time it takes to walk them, play with them, let them out during the day when you're gone at work, etc. It is a very common statement in the USA.
"I don't have the time for a dog."（犬を世話する時間がない）と聞くと、ネイティブスピーカーは普通、仕事でいない昼間の間犬を家の外に出したり、遊んだり、散歩させたりする時間について言っていると理解します。アメリカではよく聞くフレーズです。
It's too troublesome for me to walk a dog every day.
I don't want the hassle of having to walk a dog daily.
1) "Taking a dog for a walk is an inconvenience."
- This is similar to stating that you are too lazy to walk a dog. However, it could also mean that you have a busy lifestyle and that you don't have time to do it.
2) "It's too troublesome for me to walk a dog every day."
- This is similar to sentence 1. It can either mean that you are too lazy to spend time for the dog's needs, or you are too busy.
3) "I don't want the hassle of having to walk a dog daily."
- 'hassle' means an annoying inconvenience, so this sentence states that you do not want the necessary responsibilities of walking a dog because it will be a big inconvenience for you.
1) "Taking a dog for a walk is an inconvenience."（犬を散歩に連れて行くのは面倒）
- これは'I'm too lazy to walk a dog'（ものぐさで犬の散歩ができない）と似ていますが、忙しくて散歩させる時間がないという意味になることもあります。
2) "It's too troublesome for me to walk a dog every day."（犬を毎日散歩させるのは面倒）
- これは一つ目の文と似ています。ものぐさで犬の世話ができない、もしくは、忙しくて時間がないという意味になります。
3) "I don't want the hassle of having to walk a dog daily."（毎日犬を散歩させないといけなくなるのは大変だから嫌だ）
- 'hassle'は「面倒なこと」という意味です。ですからこの文は、犬を散歩させないといけなくなるのは面倒だから嫌だと言っています。
Dogs are very active and I don't want to take them on walks.
Dogs need to move, and going on walks isn't my thing.
The two sentences you see provided above are great ways to express to your listener that you do not want a dog because you do not want to take it on walks. In the second sentence you will see the word thing. If something is your thing that means it is your hobby. This is a word that is appropriate for informal settings.
上記二つの例文は、散歩をさせるのが嫌なので犬を飼いたくないと伝える素晴らしい言い方です。
二つ目の例文には"thing"という単語が使われています。"___ is my thing"で「___は自分の趣味だ」という意味になります。この単語はインフォーマルな場面に適しています。
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