Optimising what @MattObert said:

• y3iw
• /red dogEnter
• c3iwCtrl-r0Esc
• n. etc.

In detail:

• y3iw yanks philosophical chicken; this is marginally better than y2W because the latter includes a trailing space; the iw part also makes sure the yank still works when you start with the cursor in the middle of the first word, rather than at the beginning
• /red dogEnter finds the first red dog
• c3iw deletes red dog (again, without the trailing space) and switches to insert mode
• Ctrl-r0 pastes from register 0 (cf. :h i_CTRL-R and :h quote0)
• Esc switches to normal mode
• n. finds the next red dog and re-plays the last operation (i.e. replaces it with philosophical chicken)
• repeat n. as needed.

The first trick is that yanks are automatically saved to register 0. The second trick is you can paste registers in insert mode with Ctrl-r.

Other things that would help you:

• turn on line numbers: :setlocal relativenumber! number! (run it again to turn it off)
• same thing as a macro: nnoremap <silent> <Leader>, :setlocal relativenumber! number!<CR>
• use line offsets relative to the cursor line: :.,+6 s/.../.../
• replace with confirmation: :%s/red dog/philosophical chicken/gc

Take a look at Drew Neil's Vimcasts for other similar tricks. Also consider posting Vim-related questions to the Vi site.

Optimising what @MattObert said:

• y3iw
• /red dogEnter
• c3iwCtrl-r0Esc
• n. etc.

In detail:

• y3iw yanks philosophical chicken; this is marginally better than y2W because the latter includes a trailing space; the iw part also makes sure the yank still works when you start with the cursor in the middle of the first word, rather than at the beginning
• /red dogEnter finds the first red dog
• c3iw deletes red dog (again, without the trailing space) and switches to insert mode
• Ctrl-r0 pastes from register 0 (cf. :h i_CTRL-R and :h quote0)
• Esc switches to normal mode
• n. finds the next red dog and re-plays the last operation (i.e. replaces it with philosophical chicken)
• repeat n. as needed.

The first trick is that yanks are automatically saved to register 0. The second trick is you can paste registers in insert mode with Ctrl-r.

Other things that would help you:

• turn on line numbers: :setlocal relativenumber! number! (run it again to turn it off)
• same thing as a macro: nnoremap <silent> <Leader>, :setlocal relativenumber! number!<CR>
• use line offsets relative to the cursor line: :.,+6 s/.../.../
• replace with confirmation: :%s/red dog/philosophical chicken/gc

Take a look at Drew Neil's Vimcasts for other similar tricks. Also consider posting Vim-related questions to the Vi site.

Optimising what @MattObert said:

• y3iw
• /red dogEnter
• c3iwCtrl-r0Esc
• n. etc.

In detail:

• y3iw yanks philosophical chicken; this is marginally better than y2W because the latter includes a trailing space
• /red dogEnter finds the first red dog
• c3iw deletes red dog (again, without the trailing space) and switches to insert mode
• Ctrl-r0 pastes from register 0 (cf. :h i_CTRL-R and :h quote0)
• Esc switches to normal mode
• n. finds the next red dog and re-plays the last operation (i.e. replaces it with philosophical chicken)
• repeat n. as needed.

The first trick is that yanks are automatically saved to register 0. The second trick is you can paste registers in insert mode with Ctrl-r.

Other things that would help you:

• turn on line numbers: :setlocal relativenumber! number! (run it again to turn it off)
• same thing as a macro: nnoremap <silent> <Leader>, :setlocal relativenumber! number!<CR>
• use line offsets relative to the cursor line: :.,+6 s/.../.../
• replace with confirmation: :%s/red dog/philosophical chicken/gc

Take a look at Drew Neil's Vimcasts for other similar tricks. Also consider posting Vim-related questions to the Vi site.

Optimising what @MattObert said:

• y3iw
• /red dogEnter
• c3iwCtrl-r0Esc
• n. etc.

In detail:

• y3iw yanks philosophical chicken; this is marginally better than y2W because the latter includes a trailing space; the iw part also makes sure the yank still works when you start with the cursor in the middle of the first word, rather than at the beginning
• /red dogEnter finds the first red dog
• c3iw deletes red dog (again, without the trailing space) and switches to insert mode
• Ctrl-r0 pastes from register 0 (cf. :h i_CTRL-R and :h quote0)
• Esc switches to normal mode
• n. finds the next red dog and re-plays the last operation (i.e. replaces it with philosophical chicken)
• repeat n. as needed.

The first trick is that yanks are automatically saved to register 0. The second trick is you can paste registers in insert mode with Ctrl-r.

Other things that would help you:

• turn on line numbers: :setlocal relativenumber! number! (run it again to turn it off)
• same thing as a macro: nnoremap <silent> <Leader>, :setlocal relativenumber! number!<CR>
• use line offsets relative to the cursor line: :.,+6 s/.../.../
• replace with confirmation: :%s/red dog/philosophical chicken/gc

Take a look at Drew Neil's Vimcasts for other similar tricks. Also consider posting Vim-related questions to the Vi site.